Origin of micrometer-scale dislocation motion during hydrogen desorption

Motomichi Koyama, Seyedeh Mohadeseh Taheri-Mousavi, Seyedeh Mohadeseh Taheri-Mousavi, Haoxue Yan, Jinwoo Kim, Benjamin Clive Cameron, Seyed Sina Moeini-Ardakani, Ju Li, Ju Li, Cemal Cem Tasan

Science Advances　6　(23)　2020/06

DOI： 10.1126/sciadv.aaz1187 　

eISSN： 2375-2548

Gaseous hydrogen embrittlement of a Ni-free austenitic stainless steel containing 1 mass% nitrogen: Effects of nitrogen-enhanced dislocation planarity Peer-reviewed

Motomichi Koyama, Kishan Habib, Takuro Masumura, Toshihiro Tsuchiyama, Hiroshi Noguchi

International Journal of Hydrogen Energy　45　(16)　10209-10218　2020/03/20

DOI： 10.1016/j.ijhydene.2020.02.014 　

ISSN： 0360-3199

Dislocation motion at a fatigue crack tip in a high-nitrogen steel clarified through in situ electron channeling contrast imaging Peer-reviewed

Kishan Habib, Motomichi Koyama, Toshihiro Tsuchiyama, Hiroshi Noguchi

Materials Characterization　158　2019/12

DOI： 10.1016/j.matchar.2019.109930 　

ISSN： 1044-5803

Crystallographic selection rule for the propagation mode of microstructurally small fatigue crack in a laminated Ti-6Al-4V alloy: Roles of basal and pyramidal slips Peer-reviewed

Akira Maenosono, Motomichi Koyama, Yoshihisa Tanaka, Shien Ri, Qinghua Wang, Hiroshi Noguchi

International Journal of Fatigue　128　105200-105200　2019/11/01

DOI： 10.1016/j.ijfatigue.2019.105200 　

ISSN： 0142-1123

Revisiting the effects of hydrogen on deformation-induced γ-ε martensitic transformation

Motomichi Koyama, Natsuki Terao, Kaneaki Tsuzaki

Materials Letters　249　197-200　2019/08/15

DOI： 10.1016/j.matlet.2019.04.093 　

ISSN： 0167-577X

eISSN： 1873-4979

Grain refinement effect on hydrogen embrittlement resistance of an equiatomic CoCrFeMnNi high-entropy alloy Peer-reviewed

Motomichi Koyama, Kenshiro Ichii, Kaneaki Tsuzaki

International Journal of Hydrogen Energy　44　(31)　17163-17167　2019/06/21

DOI： 10.1016/j.ijhydene.2019.04.280 　

ISSN： 0360-3199

Fatigue Resistance of Laminated and Non-laminated TRIP-maraging Steels: Crack Roughness vs Tensile Strength

Zhao Zhang, Motomichi Koyama, Meimei Wang, Cemal Cem Tasan, Hiroshi Noguchi

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　50　1142-1145　2019/03/15

DOI： 10.1007/s11661-018-5081-6 　

ISSN： 1073-5623

An unconventional hydrogen effect that suppresses thermal formation of the hcp phase in fcc steels

Motomichi Koyama, Kenji Hirata, Yuji Abe, Akihiro Mitsuda, Satoshi Iikubo, Kaneaki Tsuzaki

Scientific Reports　8　2018/12/01

DOI： 10.1038/s41598-018-34542-0 　

Bone-like crack resistance in hierarchical metastable nanolaminate steels Peer-reviewed

Motomichi Koyama, Zhao Zhang, Meimei Wang, Dirk Ponge, Dierk Raabe, Kaneaki Tsuzaki, Hiroshi Noguchi, Cemal Cem Tasan

SCIENCE　355　(6329)　1055-1057　2017/03

DOI： 10.1126/science.aal2766 　

ISSN： 0036-8075

eISSN： 1095-9203

Stability of electrochemical hydrogen charging in NaCl aqueous solution containing NH<inf>4</inf>SCN: Effect of changes in solution chemistry

Saya Ajito, Yusuke Kabasawa, Hiroshi Kakinuma, Motomichi Koyama, Eiji Akiyama

Corrosion Science　249　2025/06

DOI： 10.1016/j.corsci.2025.112843 　

ISSN： 0010-938X

Hydrogen Effects on Hall–Petch Coefficient and Fracture Strength in Pure Ni and Ni-20Cr Alloy: A Macroscopic Insight of the Hydrogen Embrittlement Mechanism

Motomichi Koyama, Kota Tomatsu, Hiroshi Kakinuma, Saya Ajito, Eiji Akiyama

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　56　(3)　771-777　2025/03

DOI： 10.1007/s11661-025-07688-6 　

ISSN： 1073-5623

eISSN： 1543-1940

Semi-quantitative characterisation of coherency-dependent hydrogen diffusion at Σ3 grain boundaries in pure Ni

Hiroshi Kakinuma, Motomichi Koyama, Rama Srinivas Varanasi, Saya Ajito, Eiji Akiyama

Materials Research Letters　1-8　2025/01/24

DOI： 10.1080/21663831.2025.2457369 　

eISSN： 2166-3831

Grain boundary nanochemistry and intergranular corrosion of Fe-0.01wt.%P alloy: Roles of elemental segregations and misorientation

Saya Ajito, Kazuya Tojima, Hiroshi Kakinuma, Kohei Ikeda, Yongjie Zhang, Tomohiko Hojo, Goro Miyamoto, Motomichi Koyama, Tadashi Furuhara, Eiji Akiyama

Acta Materialia　283　120577-120577　2025/01/15

DOI： 10.1016/j.actamat.2024.120577 　

ISSN： 1359-6454

Analysis of void formation and crack propagation at grain boundaries in Al-Zn-Mg-Cu alloy

Shota Tsuchiya, Kazuyuki Shimizu, Yasuhiro Kamada, Hiroyuki Toda, Hiro Fujihara, Kyosuke Hirayama, Motomichi Koyama, Masayuki Uesugi, Akihisa Takeuchi

Keikinzoku/Journal of Japan Institute of Light Metals　75　(2)　96-102　2025

DOI： 10.2464/jilm.75.96 　

ISSN： 0451-5994

Positive strain rate dependence: optimizing TRIP effect for high-speed deformation in lean duplex stainless steel

Yongxin Wang, Lei Chen, Xingzhou Cai, Motomichi Koyama, Zhenting Wang, Xiaolong Li, Zhikun Bai, Xiaocong Ma, Miao Jin

Materials Research Letters　13　(1)　42-50　2025

DOI： 10.1080/21663831.2024.2415903 　

eISSN： 2166-3831

Stress and Plastic Strain Partitioning Behaviors and Those Contributions to Martensitic Transformation of Retained Austenite in Medium Manganese and Transformation-Induced Plasticity-Aided Bainitic Ferrite Steels

Tomohiko Hojo, Motomichi Koyama, Bakuya Kumai, Yutao Zhou, Yuki Shibayama, Ayumi Shiro, Takahisa Shobu, Hiroyuki Saitoh, Saya Ajito, Eiji Akiyama

ISIJ International　65　(2)　284-296　2025

DOI： 10.2355/isijinternational.ISIJINT-2024-268 　

ISSN： 0915-1559

Microscopic Strain Mapping: Functional Diversity and Their Demands

Motomichi Koyama, Kazuyuki Shimizu, Shien Ri, Norimitsu Koga, Hideaki Nishikawa, Tatsuya Morikawa, Hiroshi Fudouzi

Journal of the Japan Institute of Metals and Materials　88　(11)　253-269　2024/11/01

DOI： 10.2320/jinstmet.j202408 　

ISSN： 0021-4876

eISSN： 1880-6880 2433-7501

Stress-controlled hydrogen embrittlement failure in U-bend high-strength steel

Yuki Shibayama, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

International Journal of Hydrogen Energy　88　1010-1016　2024/10/28

DOI： 10.1016/j.ijhydene.2024.09.123 　

ISSN： 0360-3199

Novel Fe-Mo intermetallic composite synthesized via diffusional-displacive mixed-mode transformation

Rama Srinivas Varanasi, Srikakulapu Kiranbabu, Reina Utsumi, Hiroyuki Saitoh, Ronald Schnitzer, Eiji Akiyama, Motomichi Koyama

Materials Characterization　216　2024/10

DOI： 10.1016/j.matchar.2024.114287 　

ISSN： 1044-5803

Visualization of Microscopic Hydrogen Diffusion in Polycrystalline Pure Ni Using an Ir Complex

Saya Ajito, Hiroshi Kakinuma, Motomichi Koyama, Eiji Akiyama

Zairyo-to-Kankyo　73　(8)　194-199　2024/08/10

DOI： 10.3323/jcorr.73.194 　

ISSN： 0917-0480

eISSN： 1881-9664

Understanding crack growth within the γ′ Fe<inf>4</inf>N layer in a nitrided low carbon steel during monotonic and cyclic tensile testing

Rama Srinivas Varanasi, Motomichi Koyama, Mizuho Yokoi, Yusuke Ootani, Momoji Kubo, Kento Tanahara, Osamu Umezawa

Journal of Materials Science　59　(31)　14639-14652　2024/08

DOI： 10.1007/s10853-024-10014-x 　

ISSN： 0022-2461

eISSN： 1573-4803

ポリアニリンを用いた金属中を拡散する水素の可視化技術 Invited Peer-reviewed

Hiroshi Kakinuma, Saya Ajito, Motomichi Koyama, Eiji Akiyama

Materia Japan　63　(6)　381-389　2024/06/01

DOI： 10.2320/materia.63.381 　

ISSN： 1340-2625

eISSN： 1884-5843

Influence of austenite grain boundary misorientation on hydrogen-induced intergranular crack propagation in a medium carbon martensitic steel Peer-reviewed

Ji Hoon Kim, Goro Miyamoto, Akinobu Shibata, Tomohiko Hojo, Motomichi Koyama, Yongjie Zhang, Tadashi Furuhara

Acta Materialia　274　120036-120036　2024/05

DOI： 10.1016/j.actamat.2024.120036 　

ISSN： 1359-6454

Growth path and morphology of hydrogen-related cracks in grain-refined tempered martensitic steel produced by cyclic thermal treatment Peer-reviewed

Tingshu Chen, Yuhei Ogawa, Motomichi Koyama

International Journal of Hydrogen Energy　2024/05

DOI： 10.1016/j.ijhydene.2024.05.327 　

ISSN： 0360-3199

Mechanism of local hydrogen entry into Fe sheets induced by atmospheric corrosion: Significance of potential, pH, and rust layer thickness Peer-reviewed

Hiroshi Kakinuma, Sachiko Hiromoto, Tomohiko Hojo, Saya Ajito, Motomichi Koyama, Eiji Akiyama

Corrosion Science　232　112043-112043　2024/05

DOI： 10.1016/j.corsci.2024.112043 　

ISSN： 0010-938X

Microscopic visualization of hydrogen diffusion in UNS S32750 super duplex stainless steel: Roles of crystal structure and grain size Peer-reviewed

Hiroshi Kakinuma, Saya Ajito, Motomichi Koyama, Eiji Akiyama

International Journal of Hydrogen Energy　59　866-873　2024/03/15

DOI： 10.1016/j.ijhydene.2024.02.069 　

ISSN： 0360-3199

An atomistic study on the HELP mechanism of hydrogen embrittlement in pure metal Fe Peer-reviewed

Md Shahrier Hasan, Mehmet Fazil Kapci, Burak Bal, Motomichi Koyama, Hadia Bayat, Wenwu Xu

International Journal of Hydrogen Energy　57　60-68　2024/02/29

DOI： 10.1016/j.ijhydene.2023.12.274 　

ISSN： 0360-3199

Hydrogen Embrittlement Property of a 1.5 GPa Dual-Phase Steel Evaluated Using U-bending Test: A Comparison with Tempered Martensitic Steel with Identical Tensile Strength Peer-reviewed

Shuya Chiba, Motomichi Koyama, Tomohiko Hojo, Saya Ajito, Yuki Shibayama, Rama Srinivas Varanasi, Eiji Akiyama

ISIJ International　64　(4)　706-713　2024/02/28

DOI： 10.2355/isijinternational.isijint-2023-287 　

ISSN： 0915-1559

eISSN： 1347-5460

Hydrogen-assisted localized plasticity driven by dislocation pinning-depinning: Finite element simulations Peer-reviewed

Daisuke Sasaki, Yuki Kusaba, Motomichi Koyama

International Journal of Hydrogen Energy　56　280-288　2024/02/22

DOI： 10.1016/j.ijhydene.2023.12.053 　

ISSN： 0360-3199

Plasticity-induced Hydrogen Desorptions Associated with Hydrogen-assisted Martensitic Transformation and Deformation Twinning in Austenitic Stainless Steels

Yifei Wen, Motomichi Koyama, Tomohiko Hojo, Saya Ajito, Eiji Akiyama

ISIJ International　64　(2)　474-481　2024/01/30

DOI： 10.2355/isijinternational.isijint-2023-130 　

ISSN： 0915-1559

eISSN： 1347-5460

In situ visualization of misorientation-dependent hydrogen diffusion at grain boundaries of pure polycrystalline Ni using a hydrogen video imaging system Peer-reviewed

Hiroshi Kakinuma, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

Acta Materialia　263　119536-119536　2024/01/15

DOI： 10.1016/j.actamat.2023.119536 　

ISSN： 1359-6454

Critical role of initial multi-phase microstructure on the phase transformations during hydrogenation in Fe–Mo alloy system Peer-reviewed

Rama Srinivas Varanasi, Motomichi Koyama, Reina Utsumi, Hiroyuki Saitoh, Toyoto Sato, Shin ichi Orimo, Eiji Akiyama

International Journal of Hydrogen Energy　50　1418-1434　2024/01/02

DOI： 10.1016/j.ijhydene.2023.09.268 　

ISSN： 0360-3199

Dual grain size-effects on hydrogen-assisted fatigue crack growth in 1 GPa-class medium-carbon martensitic steel Peer-reviewed

Yuhei Ogawa, Kazuhiro Kuriyama, Motomichi Koyama

International Journal of Hydrogen Energy　50　108-115　2024/01/02

DOI： 10.1016/j.ijhydene.2023.08.317 　

ISSN： 0360-3199

Local Work-Hardening and Lüders Deformation Invariance in TRIP-Aided Medium-Mn High-Strength Steel: Significant TRIP Effect Changes in the Warm Temperature Range up to 200 ℃

Takashi MATSUNO, Yuta YAMAZAKI, Seiya MATSUBARA, Jin EGUCHI, Kazuyuki SHIMIZU, Motomichi KOYAMA, Yoshitaka OKITSU, Toshihiro TSUCHIYAMA

Journal of the Japan Society for Technology of Plasticity　2024

DOI： 10.9773/sosei.240702 　

ISSN： 0038-1586

eISSN： 1882-0166

Enhancing prior austenite grain boundary coherency by introducing partial bainite in martensitic steel

Ji Hoon Kim, Goro Miyamoto, Akinobu Shibata, Tomohiko Hojo, Motomichi Koyama, Yongjie Zhang, Tadashi Furuhara

Proceedings of International Symposia on Steel Science　2024　169-172　2024

DOI： 10.2355/isijisss.2024.0_169 　

eISSN： 2759-6621

Local Yield Stress and Its Unusual Independence on Multi-axial Stress States during Lüders Deformation of Medium-Mn, High-strength Steel

Takashi Matsuno, Koki Furukawa, Yoshitaka Okitsu, Motomichi Koyama, Toshihiro Tsuchiyama

ISIJ International　64　(5)　859-867　2024

DOI： 10.2355/isijinternational.ISIJINT-2023-326 　

ISSN： 0915-1559

Grain Refinement Effect on Resistance to Hydrogen-assisted Crack Growth in Equiatomic CoCrFeNi High-entropy Alloy with Different H Charging Conditions

Taein Kong, Haoyu Wang, Taekyung Lee, Motomichi Koyama, Eiji Akiyama

ISIJ International　64　(4)　688-695　2024

DOI： 10.2355/ISIJINTERNATIONAL.ISIJINT-2023-218 　

ISSN： 0915-1559

Visualization of Microscopic Hydrogen Diffusion in Polycrystalline Pure Ni Using an Ir Complex

Saya Ajito, Hiroshi Kakinuma, Motomichi Koyama, Eiji Akiyama

MATERIALS TRANSACTIONS　65　(11)　1436-1441　2024

DOI： 10.2320/matertrans.mt-c2024008 　

ISSN： 1345-9678

eISSN： 1347-5320

Strain rate-dependent tensile deformation behavior and fracture mechanism of Mn–N bearing lean duplex stainless steel Peer-reviewed

Yongxin Wang, Lei Chen, Lizi Shao, Shuo Hao, Motomichi Koyama, Xingzhou Cai, Xiaocong Ma, Miao Jin

Materials Science and Engineering: A　889　2024/01

DOI： 10.1016/j.msea.2023.145832 　

ISSN： 0921-5093

Hierarchical Deformation Heterogeneity during Lüders Band Propagation in an Fe-5Mn-0.1C Medium Mn Steel Clarified through in situ Scanning Electron Microscopy Peer-reviewed

Motomichi Koyama, Takayuki Yamashita, Satoshi Morooka, Zhipeng Yang, Rama Srinivas Varanasi, Tomohiko Hojo, Takuro Kawasaki, Stefanus Harjo

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　110　(3)　205-216　2024

DOI： 10.2355/tetsutohagane.TETSU-2023-052 　

ISSN： 0021-1575

Quantitative Evaluation of the Relationship between Strain and Color Change in Opal Photonic Crystal Films and Application into Complex Specimen Geometries Peer-reviewed

Yutao Zhou, Zhipeng Yang, Motomichi Koyama, Saya Ajito, Tomohiko Hojo, Hiroshi Fudouzi, Eiji Akiyama

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　110　(3)　311-320　2024

DOI： 10.2355/tetsutohagane.TETSU-2023-020 　

ISSN： 0021-1575

Stress and Plastic Strain Partitioning Behaviors and Those Contributions to Martensitic Transformation of Retained Austenite in Medium Manganese and Transformation- Induced Plasticity-Aided Bainitic Ferrite Steels Peer-reviewed

Tomohiko Hojo, Motomichi Koyama, Bakuya Kumai, Yutao Zhou, Yuki Shibayama, Ayumi Shiro, Takahisa Shobu, Hiroyuki Saitoh, Saya Ajito, Eiji Akiyama

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　110　(3)　227-240　2024

DOI： 10.2355/tetsutohagane.TETSU-2023-062 　

ISSN： 0021-1575

Local Yield Stress and its Unusual Independence on Multi-axial Stress States during Lüders Deformation of Medium-Mn, High-strength Steel Peer-reviewed

Takashi Matsuno, Koki Furukawa, Yoshitaka Okitsu, Motomichi Koyama, Toshihiro Tsuchiyama

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　110　(3)　217-226　2024

DOI： 10.2355/tetsutohagane.TETSU-2023-049 　

ISSN： 0021-1575

Microstructure and Plasticity Evolution During Lüders Deformation in an Fe-5Mn-0.1C Medium-Mn Steel Peer-reviewed

Motomichi Koyama, Takayuki Yamashita, Satoshi Morooka, Takahiro Sawaguchi, Zhipeng Yang, Tomohiko Hojo, Takuro Kawasaki, Stefanus Harjo

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　110　(3)　197-204　2024

DOI： 10.2355/tetsutohagane.TETSU-2023-038 　

ISSN： 0021-1575

eISSN： 1883-2954

Temperature dependence of hydrogen-assisted damage evolution and fracture behavior in TRIP-aided bainitic ferrite steel Peer-reviewed

Yutao Zhou, Tomohiko Hojo, Motomichi Koyama, Saya Ajito, Eiji Akiyama

Materials Science and Engineering: A　886　2023/10/17

DOI： 10.1016/j.msea.2023.145663 　

ISSN： 0921-5093

Mesoscale quantification of grain boundary character and local plasticity in hydrogen-assisted intergranular and intergranular-like cracking paths in tempered martensitic steel Peer-reviewed

Tingshu Chen, Motomichi Koyama, Takahiro Chiba, Eiji Akiyama, Kenichi Takai

Materials Science and Engineering: A　886　145718-145718　2023/10/17

DOI： 10.1016/j.msea.2023.145718 　

ISSN： 0921-5093

Hydrogen-Induced Delayed Fracture in a 1.5 GPa Dual-Phase Steel via Coalescence of Surface and Sub-surface Cracks Peer-reviewed

Rama Srinivas Varanasi, Motomichi Koyama, Yuki Shibayama, Shuya Chiba, Saya Ajito, Tomohiko Hojo, Eiji Akiyama

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　54　(8)　2989-2997　2023/08

DOI： 10.1007/s11661-023-07096-8 　

ISSN： 1073-5623

eISSN： 1543-1940

Environment-assisted cracking of AZ31 magnesium alloy in a borate buffer solution containing ammonium thiocyanate under various potentials Peer-reviewed

Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Sachiko Hiromoto, Eiji Akiyama

Corrosion Science　218　2023/07/01

DOI： 10.1016/j.corsci.2023.111195 　

ISSN： 0010-938X

Phase transformations and microstructure evolutions during depressurization of hydrogenated Fe–Mn–Si–Cr alloy Peer-reviewed

Rama Srinivas Varanasi, Motomichi Koyama, Hiroyuki Saitoh, Reina Utsumi, Toyoto Sato, Shin ichi Orimo, Eiji Akiyama

International Journal of Hydrogen Energy　48　(27)　10081-10088　2023/03/29

DOI： 10.1016/j.ijhydene.2022.11.274 　

ISSN： 0360-3199

Mechanical loading effect on the hydrogen uptake of tempered martensite steel: Elastic strain effect vs. plastic strain effect Peer-reviewed

Yota Masuda, Motomichi Koyama, Hiroshi Kakinuma, Eiji Akiyama

Materials Science and Engineering: A　862　144486-144486　2023/01/18

DOI： 10.1016/j.msea.2022.144486 　

ISSN： 0921-5093

Crack Tip Deformation during Dwell Fatigue and Its Correlation with Crack/Fracture Surface Morphologies in a Bi–Modal Ti–6Al–4V Alloy Peer-reviewed

Aoki Yuma, Koyama Motomichi, Tanaka Masaki, Tsuzaki Kaneaki

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　87　(12)　309-318　2023

DOI： 10.2320/jinstmet.J2023022 　

ISSN： 0021-4876

Effect of Stretch-forming on Hydrogen Diffusion Behavior in High-strength Steel Sheet Peer-reviewed

Hayato Nishimura, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Ken-ichi Fujita, Yuki Shibayama, Hiroshi Kakinuma, Eiji Akiyama

ISIJ International　64　(4)　637-644　2023

DOI： 10.2355/isijinternational.isijint-2023-149 　

ISSN： 0915-1559

eISSN： 1347-5460

Transformation-Induced Microcracks and Their Arrest with Different Deformation Temperatures in a Medium Mn Steel Peer-reviewed

Yutao Zhou, Motomichi Koyama, Tomohiko Hojo, Saya Ajito, Eiji Akiyama

Metallurgical and Materials Transactions A　54　(1)　153-166　2023/01

DOI： 10.1007/s11661-022-06855-3 　

ISSN： 1073-5623

eISSN： 1543-1940

Mixed type brittle fracture in 1.5 GPa dual-phase steel via {100} ferrite cleavage cracking Peer-reviewed

Rama Srinivas Varanasi, Motomichi Koyama, Yuki Shibayama, Eiji Akiyama

Materials Science and Engineering: A　857　2022/11/01

DOI： 10.1016/j.msea.2022.144021 　

ISSN： 0921-5093

Hierarchical Deformation Heterogeneity during Lüders Band Propagation in an Fe-5Mn-0.1C Medium Mn Steel Clarified through &lt;i&gt;in situ&lt;/i&gt; Scanning Electron Microscopy Peer-reviewed

Motomichi Koyama, Takayuki Yamashita, Satoshi Morooka, Zhipeng Yang, Rama Srinivas Varanasi, Tomohiko Hojo, Takuro Kawasaki, Stefanus Harjo

ISIJ International　62　(10)　2043-2053　2022/10/15

DOI： 10.2355/isijinternational.isijint-2022-098 　

ISSN： 0915-1559

eISSN： 1347-5460

Microstructure and Plasticity Evolution During Lüders Deformation in an Fe-5Mn-0.1C Medium-Mn Steel Peer-reviewed

Motomichi Koyama, Takayuki Yamashita, Satoshi Morooka, Takahiro Sawaguchi, Zhipeng Yang, Tomohiko Hojo, Takuro Kawasaki, Stefanus Harjo

ISIJ International　62　(10)　2036-2042　2022/10/15

DOI： 10.2355/isijinternational.isijint-2021-510 　

ISSN： 0915-1559

eISSN： 1347-5460

Strain Rate and Temperature Effects on Hydrogen Embrittlement of Stable and Metastable High-Entropy Alloys Peer-reviewed

M. Koyama, K. Ichii, K. Tsuzaki

Physical Mesomechanics　25　(5)　385-392　2022/10

DOI： 10.1134/S1029959922050010 　

ISSN： 1029-9599

eISSN： 1990-5424

Transition mechanism of cycle- to time-dependent acceleration of fatigue crack-growth in 0.4 %C Cr-Mo steel in a pressurized gaseous hydrogen environment Peer-reviewed

Atsuki Setoyama, Yuhei Ogawa, Masami Nakamura, Yuya Tanaka, Tingshu Chen, Motomichi Koyama, Hisao Matsunaga

International Journal of Fatigue　163　107039-107039　2022/10

DOI： 10.1016/j.ijfatigue.2022.107039 　

ISSN： 0142-1123

In situ 2D mapping of hydrogen entry into an Fe sheet under a droplet of NaCl solution using a hydrogenochromic sensor Peer-reviewed

Hiroshi Kakinuma, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Sachiko Hiromoto, Eiji Akiyama

International Journal of Hydrogen Energy　47　(90)　38468-38476　2022/09

DOI： 10.1016/j.ijhydene.2022.09.006 　

ISSN： 0360-3199

Simultaneous observations of the corrosion behavior of an Fe sheet and the associated hydrogen distribution therein employing a hydrogenochromic sensor Peer-reviewed

Hiroshi Kakinuma, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Sachiko Hiromoto, Eiji Akiyama

Corrosion Science　206　110534-110534　2022/09

DOI： 10.1016/j.corsci.2022.110534 　

ISSN： 0010-938X

Hydrogen-accelerated fatigue crack growth of equiatomic Fe–Cr–Ni–Mn–Co high-entropy alloy evaluated by compact tension testing Peer-reviewed

Motomichi Koyama, Shunsuke Mizumachi, Eiji Akiyama, Kaneaki Tsuzaki

Materials Science and Engineering A　848　2022/07/19

DOI： 10.1016/j.msea.2022.143394 　

ISSN： 0921-5093

Synergistic effects of hydrogen and deformation temperature on mechanical properties of TRIP-aided bainitic ferrite steel Peer-reviewed

Yutao Zhou, Tomohiko Hojo, Motomichi Koyama, Saya Ajito, Eiji Akiyama

Materials Science and Engineering A　842　2022/05/11

DOI： 10.1016/j.msea.2022.143070 　

ISSN： 0921-5093

Comparative study of stress and strain partitioning behaviors in medium manganese and transformation-induced plasticity-aided bainitic ferrite steels

Tomohiko Hojo, Motomichi Koyama, Bakuya Kumai, Yuki Shibayama, Ayumi Shiro, Takahisa Shobu, Hiroyuki Saitoh, Saya Ajito, Eiji Akiyama

Scripta Materialia　210　2022/03/15

DOI： 10.1016/j.scriptamat.2021.114463 　

ISSN： 1359-6462

Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique

Yutao Zhou, Tomohiko Hojo, Amane Kitahara, Yusuke Onuki, Shigeo Sato, Motomichi Koyama, Eiji Akiyama

Materialia　21　2022/03

DOI： 10.1016/j.mtla.2022.101317 　

eISSN： 2589-1529

Effects of Thermomechanical Processing on Hydrogen Embrittlement Properties of Ultrahigh-Strength TRIP-Aided Bainitic Ferrite Steels

Tomohiko Hojo, Yutao Zhou, Junya Kobayashi, Koh Ichi Sugimoto, Yoshito Takemoto, Akihiko Nagasaka, Motomichi Koyama, Saya Ajito, Eiji Akiyama

Metals　12　(2)　2022/02

DOI： 10.3390/met12020269 　

eISSN： 2075-4701

Effects of Ammonium Thiocyanate and pH of Aqueous Solutions on Hydrogen Absorption into Iron under Cathodic Polarization

Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

Tetsu-to-Hagane　108　(11)　857-863　2022

DOI： 10.2355/tetsutohagane.tetsu-2022-043 　

ISSN： 0021-1575

eISSN： 1883-2954

Quantitative Evaluation of the Relationship between Strain and Color Change in Opal Photonic Crystal Films and Application into Complex Specimen Geometries Peer-reviewed

Yutao Zhou, Zhipeng Yang, Motomichi Koyama, Saya Ajito, Tomohiko Hojo, Hiroshi Fudouzi, Eiji Akiyama

ISIJ International　2022

DOI： 10.2355/isijinternational.isijint-2022-054 　

ISSN： 0915-1559

eISSN： 1347-5460

Effect of Stretch-forming on Hydrogen Diffusion Behavior in High-strength Steel Sheet

Hayato Nishimura, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Ken-ichi Fujita, Yuki Shibayama, Hiroshi Kakinuma, Eiji Akiyama

Tetsu-to-Hagane　108　(5)　316-324　2022

DOI： 10.2355/tetsutohagane.tetsu-2021-096 　

ISSN： 0021-1575

eISSN： 1883-2954

Multi-Probe Characterization of Plasticity Heterogeneity: Requirement of Alloy Design Considering Dislocation Planarity for Developing Crack-Resistant Ni–Cr Alloys

Taein Kong, Motomichi Koyama, Misaho Yamamura, Eiji Akiyama

MATERIALS TRANSACTIONS　63　(1)　88-91　2022/01/01

DOI： 10.2320/matertrans.mt-m2021191 　

ISSN： 1345-9678

eISSN： 1347-5320

Cr Effects on the Local Plasticity Evolution and Fracture Behaviors of Ni–Cr Alloys Tensile–Tested under Hydrogen Charging Peer-reviewed

Naohiro Kobayashi, Motomichi Koyama, Misaho Yamamura, Tomohiko Hojo, Eiji Akiyama

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　86　(5)　77-84　2022

DOI： 10.2320/JINSTMET.J2021054 　

ISSN： 0021-4876

Real-Time Visualization of Hydrogen Distribution in Metals Using Polyaniline: An Ultrasensitive Hydrogenochromic Sensor

Hiroshi Kakinuma, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

Advanced Materials Interfaces　9　(18)　2022

DOI： 10.1002/admi.202101984 　

eISSN： 2196-7350

Hydrogen Embrittlement Behavior of Pure Ni and Ni-20Cr Alloy with Different Grain Sizes

Naohiro Kobayashi, Motomichi Koyama, Kenji Kobayashi, Tomohiko Hojo, Eiji Akiyama

Materials Transactions　63　(2)　247-256　2022

DOI： 10.2320/matertrans.MT-M2021170 　

ISSN： 1345-9678

Annealing Time Effects on Mechanically Long Fatigue Crack Growth of TRIP-maraging Steels

Tomoki Mizoguchi, Motomichi Koyama, Hiroshi Noguchi

ISIJ International　62　(2)　399-401　2022

DOI： 10.2355/isijinternational.ISIJINT-2021-093 　

ISSN： 0915-1559

Factors Distinguishing Hydrogen-Assisted Intergranular and Intergranular-Like Fractures in a Tempered Lath Martensitic Steel

Tingshu Chen, Takahiro Chiba, Motomichi Koyama, Eiji Akiyama, Kenichi Takai

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　53　(5)　1645-1658　2022

DOI： 10.1007/s11661-022-06608-2 　

ISSN： 1073-5623

Pre-straining alters hydrogen-assisted cracking site and local hydrogen diffusivity in a nitrogen-doped duplex steel

Milene Yumi Maeda, Motomichi Koyama, Hayato Nishimura, Osvaldo Mitsuyuki Cintho, Eiji Akiyama

Scripta Materialia　207　114272-114272　2022/01

DOI： 10.1016/j.scriptamat.2021.114272 　

ISSN： 1359-6462

Notch shape dependence of fatigue crack extension in equiatomic CrMnFeCoNi high-entropy alloy

Kai Suzuki, Shigeru Hamada, Motomichi Koyama, Kaneaki Tsuzaki, Hiroshi Noguchi

International Journal of Fatigue　153　2021/12

DOI： 10.1016/j.ijfatigue.2021.106481 　

ISSN： 0142-1123

Hydrogenation treatment under several gigapascals assists diffusionless transformation in a face-centered cubic steel Peer-reviewed

Motomichi Koyama, Hiroyuki Saitoh, Toyoto Sato, Shin-ichi Orimo, Eiji Akiyama

Scientific Reports　11　(1)　2021/12

DOI： 10.1038/s41598-021-98938-1 　

eISSN： 2045-2322

Hierarchical Characteristics of Hydrogen-Assisted Crack Growth and Microstructural Strain Evolution in Tempered Martensitic Steels: Case of Quasi-cleavage Fracture

Tingshu Chen, Takahiro Chiba, Motomichi Koyama, Akinobu Shibata, Eiji Akiyama, Kenichi Takai

Metallurgical and Materials Transactions A　52　(10)　4703-4713　2021/10

DOI： 10.1007/s11661-021-06423-1 　

ISSN： 1073-5623

eISSN： 1543-1940

Twinning-Induced Plasticity (TWIP) Steel Invited Peer-reviewed

Motomichi Koyama

Encyclopedia of Materials: Metals and Alloys　95-105　2021/09/01

DOI： 10.1016/B978-0-12-819726-4.00067-3 　

Hydrogen embrittlement and associated surface crack growth in fine-grained equiatomic CoCrFeMnNi high-entropy alloys with different annealing temperatures evaluated by tensile testing under in situ hydrogen charging Peer-reviewed

Haoyu Wang, Motomichi Koyama, Tomohiko Hojo, Eiji Akiyama

International Journal of Hydrogen Energy　46　(65)　33028-33038　2021/09

DOI： 10.1016/j.ijhydene.2021.07.136 　

ISSN： 0360-3199

Depressurization-induced diffusionless transformation in pure iron hydrogenated under several gigapascals Peer-reviewed

Motomichi Koyama, Hiroyuki Saitoh, Toyoto Sato, Shin-ichi Orimo, Eiji Akiyama

Materials Letters: X　11　100078-100078　2021/09

DOI： 10.1016/j.mlblux.2021.100078 　

ISSN： 2590-1508

eISSN： 2590-1508

Strain rate sensitivity of hydrogen-assisted ε-martensitic transformation and associated hydrogen embrittlement in high-Mn steel Peer-reviewed

Chunxi Hao, Motomichi Koyama, Saya Ajito, Eiji Akiyama

International Journal of Hydrogen Energy　46　(53)　27221-27233　2021/08

DOI： 10.1016/j.ijhydene.2021.05.162 　

ISSN： 0360-3199

Effect of austempering treatment on the microstructure and mechanical properties of 0.4C–1.5Si-1.5Mn TRIP-aided bainitic ferrite steel

Yutao Zhou, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

Materials Science and Engineering: A　819　141479-141479　2021/07

DOI： 10.1016/j.msea.2021.141479 　

ISSN： 0921-5093

Effects of Stress and Plastic Strain on Hydrogen Embrittlement Fracture of a U-bent Martensitic Steel Sheet

Yuki Shibayama, Tomohiko Hojo, Motomichi Koyama, Hiroyuki Saitoh, Ayumi Shiro, Ryo Yasuda, Takahisa Shobu, Takashi Matsuno, Eiji Akiyama

ISIJ International　61　(4)　1322-1329　2021/04/15

DOI： 10.2355/isijinternational.isijint-2020-569 　

ISSN： 0915-1559

eISSN： 1347-5460

Roles of Hydrogen Content and Pre-strain on Damage Evolution of TRIP-aided Bainitic Ferrite Steel

Virendra Kumar Verma, Motomichi Koyama, Bakuya Kumai, Tomohiko Hojo, Eiji Akiyama

ISIJ International　61　(4)　1309-1314　2021/04/15

DOI： 10.2355/isijinternational.isijint-2020-514 　

ISSN： 0915-1559

eISSN： 1347-5460

Effects of Ammonium Thiocyanate and pH of Aqueous Solutions on Hydrogen Absorption into Iron under Cathodic Polarization

Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama

ISIJ International　61　(4)　1209-1214　2021/04/15

DOI： 10.2355/isijinternational.isijint-2020-551 　

ISSN： 0915-1559

eISSN： 1347-5460

Effects of Residual Stress on Hydrogen Embrittlement of a Stretch-Formed Tempered Martensitic Steel Sheet

Hayato Nishimura, Tomohiko Hojo, Saya Ajito, Yuki Shibayama, Motomichi Koyama, Hiroyuki Saitoh, Ayumi Shiro, Ryo Yasuda, Takahisa Shobu, Eiji Akiyama

ISIJ International　61　(4)　1170-1178　2021/04/15

DOI： 10.2355/isijinternational.isijint-2020-492 　

ISSN： 0915-1559

eISSN： 1347-5460

Novel −75°C SEM cooling stage: application for martensitic transformation in steel

Kaneaki Tsuzazki, Motomichi Koyama, Ryosuke Sasaki, Keiichiro Nakafuji, Kazushi Oie, Akinobu Shibata, Takashi Gondo, Hiroya Miyazaki, Hiroshi Akamine, Minoru Nishida

Microscopy　70　(2)　250-254　2021/03/24

DOI： 10.1093/jmicro/dfaa051 　

ISSN： 2050-5698

eISSN： 2050-5701

Effects of matrix structure and nitrogen content on fatigue properties of ultrahigh-strength low alloy trip-aided steels

Tomohiko Hojo, Junya Kobayashi, Koh Ichi Sugimoto, Yoshito Takemoto, Akihiko Nagasaka, Motomichi Koyama, Eiji Akiyama

ISIJ International　61　(2)　591-598　2021/02/15

DOI： 10.2355/isijinternational.ISIJINT-2020-392 　

ISSN： 0915-1559

Fatigue crack growth at different frequencies and temperatures in an fe-based metastable high-entropy alloy

Motomichi Koyama, Takeshi Eguchi, Kaneaki Tsuzaki

ISIJ International　61　(2)　641-647　2021/02/15

DOI： 10.2355/isijinternational.ISIJINT-2020-504 　

ISSN： 0915-1559

Three-dimensional characterization of low-cycle fatigue crack morphology in TRIP-maraging steel: Crack closure, geometrical uncertainty and wear

Zhao Zhang, Motomichi Koyama, Kaneaki Tsuzaki, Hiroshi Noguchi

International Journal of Fatigue　143　2021/02

DOI： 10.1016/j.ijfatigue.2020.106032 　

ISSN： 0142-1123

Hydrogen-assisted damage evolution in nitrogen-doped duplex stainless steel

Milene Yumi Maeda, Motomichi Koyama, Hayato Nishimura, Osvaldo Mitsuyuki Cintho, Eiji Akiyama

International Journal of Hydrogen Energy　46　(2)　2716-2728　2021/01/06

DOI： 10.1016/j.ijhydene.2020.10.152 　

ISSN： 0360-3199

Hydrogen-assisted crack propagation in pre-strained twinning-induced plasticity steel: From initiation at a small defect to failure

Abbas Mohammadi, Motomichi Koyama, Gregory Gerstein, Hans Jürgen Maier, Hiroshi Noguchi

ISIJ International　61　(4)　1278-1286　2021

DOI： 10.2355/isijinternational.ISIJINT-2019-510 　

ISSN： 0915-1559

Annealing time effects on mechanically long fatigue crack growth of TRIP-maraging steels

Tomoki Mizoguchi, Motomichi KoyaMa, Hiroshi Noguchi

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　107　(4)　321-324　2021

DOI： 10.2355/TETSUTOHAGANE.TETSU-2020-106 　

ISSN： 0021-1575

Effects of Residual Stress on Hydrogen Embrittlement of a Stretch-Formed Tempered Martensitic Steel Sheet

Hayato Nishimura, Tomohiko Hojo, Saya Ajito, Yuki Shibayama, Motomichi Koyama, Hiroyuki Saitoh, Ayumi Shiro, Ryo Yasuda, Takahisa Shobu, Eiji Akiyama

Tetsu-to-Hagane　107　(9)　760-768　2021

DOI： 10.2355/tetsutohagane.tetsu-2021-055 　

ISSN： 0021-1575

eISSN： 1883-2954

Availability of Opal Photonic Crystal Films for Visualizing Heterogeneous Strain Evolution in Steels: Example of Lüders Deformation

Zhipeng Yang, Motomichi Koyama, Hiroshi Fudouzi, Tomohiko Hojo, Eiji Akiyama

Tetsu-to-Hagane　107　(8)　681-686　2021

DOI： 10.2355/tetsutohagane.tetsu-2021-028 　

ISSN： 0021-1575

eISSN： 1883-2954

Effects of Matrix Structure and Nitrogen Content on Fatigue Properties of Ultrahigh-Strength Low Alloy TRIP-Aided Steels

Tomohiko Hojo, Junya Kobayashi, Koh-ichi Sugimoto, Yoshito Takemoto, Akihiko Nagasaka, Motomichi Koyama, Eiji Akiyama

Tetsu-to-Hagane　107　(8)　672-680　2021

DOI： 10.2355/tetsutohagane.tetsu-2021-015 　

ISSN： 0021-1575

eISSN： 1883-2954

Stacking fault aggregation during cooling composing FCC–HCP martensitic transformation revealed by in-situ electron channeling contrast imaging in an Fe-high Mn alloy

Motomichi Koyama, Misaki Seo, Keiichiro Nakafuji, Kaneaki Tsuzaki

Science and Technology of Advanced Materials　22　(1)　135-140　2021

DOI： 10.1080/14686996.2021.1877570 　

ISSN： 1468-6996

eISSN： 1878-5514

Hydrogen embrittlement behavior of pure ni and ni–20cr alloy with different grain sizes

Naohiro Kobayashi, Motomichi Koyama, Kenji Kobayashi, Tomohiko Hojo, Eiji Akiyama

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　85　(2)　49-58　2021

DOI： 10.2320/JINSTMET.J2020036 　

ISSN： 0021-4876

{111} trace analysis in ECC images-toward in-situ observation of deformation behavior in FCC bulk specimens

Motomichi Koyama, Keiichiro Nakafuji, Kaneaki Tsuzaki

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　85　(1)　17-22　2021

DOI： 10.2320/JINSTMET.JD202003 　

ISSN： 0021-4876

Quantitative Evaluation of Hydrogen Effects on Evolutions of Deformation-Induced ε-Martensite and Damage in a High-Mn Steel

Chunxi Hao, Motomichi Koyama, Eiji Akiyama

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　51　(12)　6184-6194　2020/12

DOI： 10.1007/s11661-020-06021-7 　

ISSN： 1073-5623

In-Situ Electron Channeling Contrast Imaging under Tensile Loading: Residual Stress, Dislocation Motion, and Slip Line Formation Peer-reviewed

Keiichiro Nakafuji, Motomichi Koyama, Kaneaki Tsuzaki

Scientific Reports　10　(1)　2020/12/01

DOI： 10.1038/s41598-020-59429-x 　

eISSN： 2045-2322

Availability of Opal Photonic Crystal Films for Visualizing Heterogeneous Strain Evolution in Steels: Example of Lüders Deformation Peer-reviewed

Zhipeng Yang, Motomichi Koyama, Hiroshi Fudouzi, Tomohiko Hojo, Eiji Akiyama

ISIJ International　60　(11)　2604-2608　2020/11/15

DOI： 10.2355/isijinternational.ISIJINT-2020-223 　

ISSN： 0915-1559

eISSN： 1347-5460

Pre-strain effects on critical stress and hydrogen content for hydrogen-induced quasi-cleavage fracture in a TRIP-aided bainitic ferrite steel: Martensitic transformation, matrix damage, and strain aging

Bakuya Kumai, Tomohiko Hojo, Motomichi Koyama, Eiji Akiyama, Hiroyuki Waki, Akihiko Nagasaka

International Journal of Hydrogen Energy　45　(51)　27920-27928　2020/10/16

DOI： 10.1016/j.ijhydene.2020.07.036 　

ISSN： 0360-3199

Shallow crack effect on evaluation of residual tensile strength: Harmless and stable cracks in finite-sized structure made of ductile metals

He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　109　2020/10

DOI： 10.1016/j.tafmec.2020.102734 　

ISSN： 0167-8442

Application of an iridium complex for detecting hydrogen permeation through pure iron Peer-reviewed

Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Ken ichi Fujita, Eiji Akiyama

International Journal of Hydrogen Energy　45　(46)　25580-25586　2020/09/21

DOI： 10.1016/j.ijhydene.2020.06.113 　

ISSN： 0360-3199

Hydrogen embrittlement resistance of pre-strained ultra-high-strength low alloy TRIP-aided steel

Tomohiko Hojo, Bakuya Kumai, Motomichi Koyama, Eiji Akiyama, Hiroyuki Waki, Hiroyuki Saitoh, Ayumi Shiro, Ryo Yasuda, Takahisa Shobu, Akihiko Nagasaka

International Journal of Fracture　224　(2)　253-260　2020/08/01

DOI： 10.1007/s10704-020-00451-5 　

ISSN： 0376-9429

eISSN： 1573-2673

Distinguishing geometric and metallurgic hydrogen-embrittlement susceptibilities in pre-cracked structures made of interstitial-free steel under monotonic tension

He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　108　2020/08

DOI： 10.1016/j.tafmec.2020.102574 　

ISSN： 0167-8442

Equivalence between shallow notch and shallow crack in structural failure caused by plastic instability

He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　108　2020/08

DOI： 10.1016/j.tafmec.2020.102577 　

ISSN： 0167-8442

Influence of dynamic-strain aging due to excess Mg on fatigue crack growth rate scatter in Al6061-T6 alloy

Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　108　2020/08

DOI： 10.1016/j.tafmec.2020.102617 　

ISSN： 0167-8442

Effects of hydrogen content that alters damage evolution mechanisms in SUH 660 precipitation-strengthened Fe–Cr–Ni steel

Virendra Kumar Verma, Motomichi Koyama, Shigeru Hamada, Eiji Akiyama

Materials Science and Engineering A　791　2020/07/22

DOI： 10.1016/j.msea.2020.139750 　

ISSN： 0921-5093

Simplified stress field determination for an inclined crack and interaction between two cracks under tension

Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　107　2020/06

DOI： 10.1016/j.tafmec.2020.102561 　

ISSN： 0167-8442

Fatigue behavior in an Fe-N binary ferritic steel: Similarity and difference between carbon and nitrogen Peer-reviewed

Kishan Habib, Motomichi Koyama, Eisaku Sakurada, Nobuyuki Yoshimura, Tatsuo Yokoi, Kohsaku Ushioda, Kaneaki Tsuzaki, Hiroshi Noguchi

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　106　(6)　123-129　2020/06

DOI： 10.2355/tetsutohagane.TETSU-2019-051 　

ISSN： 0021-1575

Thermal Stability of Resistance to Propagation of Mechanically Small Fatigue-cracks in an Fe-N Binary Ferritic Steel Peer-reviewed

Motomichi Koyama, Kishan Habib, Tatsuo Yokoi, Eisaku Sakurada, Nobuyuki Yoshimura, Kohsaku Ushioda, Kaneaki Tsuzaki, Hiroshi Noguchi

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　106　(6)　130-138　2020/06

DOI： 10.2355/tetsutohagane.TETSU-2019-091 　

ISSN： 0021-1575

Influence of Mn addition on fatigue limit and coaxing effect in ferritic steel containing solute carbon Peer-reviewed

Yusui Uchida, Motomichi Koyama, Yoshihiro Fukushima, Kaneaki Tsuzaki

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　106　(6)　112-122　2020/06

DOI： 10.2355/tetsutohagane.TETSU-2019-092 　

ISSN： 0021-1575

Fundamental criterion K<inf>trans</inf> for failure analysis of hydrogen-assisted cracks in notched specimens of pure Ni Peer-reviewed

Tingshu Chen, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　107　2020/06

DOI： 10.1016/j.tafmec.2020.102556 　

ISSN： 0167-8442

Multiple damage mechanisms facilitated by planar dislocation glide in a commercial-grade precipitation-strengthened Fe–Ni–Cr-based steel Peer-reviewed

Virendra Kumar Verma, Motomichi Koyama, Shigeru Hamada, Eiji Akiyama

Materials Science and Engineering A　782　139250　2020/04

DOI： 10.1016/j.msea.2020.139250 　

ISSN： 0921-5093

Planar slip-driven fatigue crack initiation and propagation in an equiatomic CrMnFeCoNi high-entropy alloy Peer-reviewed

Kai Suzuki, Motomochi Koyama, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi

International Journal of Fatigue　133　2020/04

DOI： 10.1016/j.ijfatigue.2019.105418 　

ISSN： 0142-1123

Plastic deformation sequence and strain gradient characteristics of hydrogen-induced delayed crack propagation in single-crystalline Fe–Si alloy Peer-reviewed

Thanh Thuong Huynh, Motomichi Koyama, Yoshimasa Takahashi, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi

Scripta Materialia　178　99-103　2020/03/15

DOI： 10.1016/j.scriptamat.2019.11.012 　

ISSN： 1359-6462

Fatigue crack propagation modes: plastic deformation mode and damage accumulation mode Peer-reviewed

Shigeru Hamada, Kejin Zhang, Motomichi Koyama, Masaharu Ueda, Hiroshi Noguchi

International Journal of Fracture　222　(1-2)　111-122　2020/03/01

DOI： 10.1007/s10704-020-00433-7 　

ISSN： 0376-9429

eISSN： 1573-2673

Strain rate and hydrogen effects on crack growth from a notch in a Fe-high-Mn steel containing 1.1 wt% solute carbon Peer-reviewed

Hina Najam, Motomichi Koyama, Burak Bal, Eiji Akiyama, Kaneaki Tsuzaki

International Journal of Hydrogen Energy　45　(1)　1125-1139　2020/01/01

DOI： 10.1016/j.ijhydene.2019.10.227 　

ISSN： 0360-3199

Growth behavior of a mechanically long fatigue crack in an FeCrNiMnCo high entropy alloy: A comparison with an austenitic stainless steel Peer-reviewed

Shunsuke Mizumachi, Motomichi Koyama, Yoshihiro Fukushima, Kaneaki Tsuzaki

ISIJ International　60　(1)　175-181　2020

DOI： 10.2355/isijinternational.ISIJINT-2019-230 　

ISSN： 0915-1559

Transformation-assisted hydrogen desorption during deformation in steels: Examples of αʹ- and ε-martensite Peer-reviewed

T. Hojo, M. Koyama, N. Terao, K. Tsuzaki, E. Akiyama

International Journal of Hydrogen Energy　In press　2019/12

Effect analysis of stress-intensity-factor-range decreasing rate for obtaining threshold stress-intensity-factor-range Peer-reviewed

Bochuan Li, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　104　2019/12

DOI： 10.1016/j.tafmec.2019.102377 　

ISSN： 0167-8442

A patient-specific numerical modeling of the spontaneous coronary artery dissection in relation to atherosclerosis Peer-reviewed

Alireza Karimi, Reza Razaghi, Motomichi Koyama

Computer Methods and Programs in Biomedicine　182　2019/12

DOI： 10.1016/j.cmpb.2019.105060 　

ISSN： 0169-2607

eISSN： 1872-7565

Mode I fatigue crack growth induced by strain-aging in precipitation-hardened aluminum alloys Peer-reviewed

Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

Theoretical and Applied Fracture Mechanics　104　2019/12

DOI： 10.1016/j.tafmec.2019.102340 　

ISSN： 0167-8442

Detection of hydrogen effusion before, during, and after martensitic transformation: Example of multiphase transformation-induced plasticity steel

Motomichi Koyama, Daisuke Yamasaki, Arisa Ikeda, Tomohiko Hojo, Eiji Akiyama, Kenichi Takai, Kaneaki Tsuzaki

International Journal of Hydrogen Energy　44　(47)　26028-26035　2019/10/04

DOI： 10.1016/j.ijhydene.2019.07.254 　

ISSN： 0360-3199

Effect of Hydrogen on the Substructure of Lenticular Martensite in Fe-31Ni Alloy Peer-reviewed

Akinobu Shibata, Masanori Enoki, Nahoko Saji, Hirotaka Tai, Motomichi Koyama, Hiroshi Ohtani, Nobuhiro Tsuji, Kaneaki Tsuzaki

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　50　(9)　4027-4036　2019/09/15

DOI： 10.1007/s11661-019-05320-y 　

ISSN： 1073-5623

Data of dynamic microscale strain distributions of Ti-6Al-4V alloys in dwell fatigue tests

Qinghua Wang, Shien Ri, Akira Maenosono, Yoshihisa Tanaka, Motomichi Koyama

Data in Brief　25　2019/08

DOI： 10.1016/j.dib.2019.104338 　

ISSN： 2352-3409

First-Principles Study of Chemical Driving Force for Face Centered Cubic to Hexagonal Close Packed Martensitic Transformation in Hydrogen-Charged Iron

Y. Kuroki, S. Kawano, S. Iikubo, H. Ohtani, M. Koyama, K. Tsuzaki

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　50　(7)　3019-3023　2019/07/15

DOI： 10.1007/s11661-019-05237-6 　

ISSN： 1073-5623

Strain-rate sensitivity of hydrogen-assisted damage evolution and failure in dual-phase steel: From vacancy to micrometer-scale void growth

T. Kumamoto, M. Koyama, K. Sato, K. Tsuzaki

Engineering Fracture Mechanics　216　2019/07

DOI： 10.1016/j.engfracmech.2019.106513 　

ISSN： 0013-7944

1-second-resolved strain mapping in Ti-6Al-4V alloys during dwell fatigue in SEM by video sampling moiré Peer-reviewed

Qinghua Wang, Shien Ri, Akira Maenosono, Yoshihisa Tanaka, Motomichi Koyama

Mechanics of Materials　133　63-70　2019/06/01

DOI： 10.1016/j.mechmat.2019.03.002 　

ISSN： 0167-6636

Enhancement of hydrogen embrittlement resistance of Fe-Mn-C twinning-induced plasticity steel by partial recrystallization technique Peer-reviewed

Tak Min Park, Min Tae Kim, Kyeong Ho Baik, Motomichi Koyama, Jeongho Han

Materials Characterization　151　221-226　2019/05/01

DOI： 10.1016/j.matchar.2019.03.014 　

ISSN： 1044-5803

Lowering Strain Rate Simultaneously Enhances Carbon- and Hydrogen-Induced Mechanical Degradation in an Fe-33Mn-1.1C Steel

Ibrahim Burkay Tuğluca, Motomichi Koyama, Yusaku Shimomura, Burak Bal, Demircan Canadinc, Eiji Akiyama, Kaneaki Tsuzaki

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　50　(3)　1137-1141　2019/03/15

DOI： 10.1007/s11661-018-5080-7 　

ISSN： 1073-5623

Growth behavior of a mechanically long fatigue crack in an FeCrNiMnCo high entropy alloy: A comparison with an austenitic stainless steel

Shunsuke Mizumachi, Motomichi Koyama, Yoshihiro Fukushima, Kaneaki Tsuzaki

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　105　(2)　93-99　2019/02

DOI： 10.2355/tetsutohagane.TETSU-2018-073 　

ISSN： 0021-1575

EBSD and ECCI based assessments of inhomogeneous plastic strain evolution coupled with digital image correlation

Ryohei Kakimoto, Motomichi Koyama, Kaneaki Tsuzaki

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　105　(2)　100-108　2019/02

DOI： 10.2355/tetsutohagane.TETSU-2018-072 　

ISSN： 0021-1575

Understanding the damage initiation mechanism of precipitation-strengthened Fe-Ni-Cr based austenitic steel

Virendra Kumar Verma, Shigeru Hamada, Motomichi Koyama

Materials Today: Proceedings　26　3081-3084　2019

DOI： 10.1016/j.matpr.2020.02.637 　

ISSN： 2214-7853

Evolution of quasi-brittle hydrogen-assisted damages in a dual-phase steel

Tsubasa Kumamoto, Motomichi Koyama, Koichi Sato, Kaneaki Tsuzaki

Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　83　(7)　221-230　2019

DOI： 10.2320/jinstmet.J2019008 　

ISSN： 0021-4876

ECCI Characterization of Dislocation Structures at a Non-propagating Fatigue Crack Tip: Toward Understanding the Effects of Mn-C and Cr-N Couples on Crack Growth Resistance

Kishan Habib, Motomichi Koyama, Toshihiro Tsuchiyama, Hiroshi Noguchi

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　50　426-435　2019/01/01

DOI： 10.1007/s11661-018-4972-x 　

ISSN： 1073-5623

Resistance to mechanically small fatigue crack growth in ultrafine grained interstitial-free steel fabricated by accumulative roll-bonding Peer-reviewed

X. Lin, M. Koyama, S. Gao, N. Tsuji, K. Tsuzaki, H. Noguchi

International Journal of Fatigue　118　117-125　2019/01

DOI： 10.1016/j.ijfatigue.2018.09.002 　

ISSN： 0142-1123

EBSD- And ECCI-based Assessments of Inhomogeneous Plastic Strain Evolution Coupled with Digital Image Correlation Peer-reviewed

Ryohei Kakimoto, Motomichi Koyama, Kaneaki Tsuzaki

ISIJ International　59　(12)　2334-2342　2019

DOI： 10.2355/isijinternational.ISIJINT-2019-232 　

ISSN： 0915-1559

Evolution of quasi-brittle hydrogen-assisted damages in a dual-phase steel Peer-reviewed

Tsubasa Kumamoto, Motomichi Koyama, Koichi Sato, Kaneaki Tsuzaki

Materials Transactions　60　(11)　2368-2377　2019

DOI： 10.2320/matertrans.MT-M2019196 　

ISSN： 1345-9678

Fatigue behavior in an Fe-N binary ferritic steel: Similarity and difference between carbon and nitrogen Peer-reviewed

Kishan Habib, Motomichi Koyama, Eisaku Sakurada, Nobuyuki Yoshimura, Tatsuo Yokoi, Kohsaku Ushioda, Kaneaki Tsuzaki, Hiroshi Noguchi

ISIJ International　59　(1)　186-191　2019/01

DOI： 10.2355/isijinternational.ISIJINT-2018-535 　

ISSN： 0915-1559

Phase stability effects on hydrogen embrittlement resistance in martensite-reverted austenite steels. Peer-reviewed

B. Cameron, Motomichi Koyama, C.C. Tasan

Metallurgical Materials Transctions A　50　(1)　29-34　2019/01

DOI： 10.1007/s11661-018-4948-x 　

Influence of stress re-distribution on hydrogen-induced fatigue crack propagation

Daisuke Sasaki, Motomichi Koyama, Hiroshi Noguchi

ISIJ International　59　1683-1690　2019/01/01

DOI： 10.2355/isijinternational.ISIJINT-2019-012 　

ISSN： 0915-1559

Roughness-induced stress shielding effect in fatigue crack propagation under Mode II loading Peer-reviewed

Shigeru Hamada, Taro Suemasu, Shuto Fukudome, Motomichi Koyama, Masaharu Ueda, Hiroshi Noguchi

International Journal of Fatigue　116　245-256　2018/11/01

DOI： 10.1016/j.ijfatigue.2018.06.029 　

ISSN： 0142-1123

Effect of shear-affected zone on fatigue crack propagation mode Peer-reviewed

Shigeru Hamada, Kejin Zhang, Jiwang Zhang, Motomichi Koyama, Tatsuo Yokoi, Hiroshi Noguchi

International Journal of Fatigue　116　36-47　2018/11/01

DOI： 10.1016/j.ijfatigue.2018.06.003 　

ISSN： 0142-1123

Optical full-field strain measurement method from wrapped sampling Moiré phase to minimize the influence of defects and its applications Peer-reviewed

Qinghua Wang, Shien Ri, Hiroshi Tsuda, Motomichi Koyama

Optics and Lasers in Engineering　110　155-162　2018/11/01

DOI： 10.1016/j.optlaseng.2018.05.020 　

ISSN： 0143-8166

First-Principles Study on Hydrogen Diffusivity in BCC, FCC, and HCP Iron

K. Hirata, S. Iikubo, M. Koyama, K. Tsuzaki, H. Ohtani

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science　49　5015-5022　2018/10/01

DOI： 10.1007/s11661-018-4815-9 　

ISSN： 1073-5623

Fatigue behavior of Fe-Cr-Ni-based metastable austenitic steels with an identical tensile strength and different solute carbon contents

Takuro Ogawa, Motomichi Koyama, Yuri Nishikura, Kaneaki Tsuzaki, Hiroshi Noguchi

ISIJ International　58　1910-1919　2018/10/01

DOI： 10.2355/isijinternational.ISIJINT-2018-098 　

ISSN： 0915-1559

Surface orientation dependence of hydrogen flux in lenticular martensite of an Fe-Ni-C alloy clarified through in situ silver decoration technique Peer-reviewed

Motomichi Koyama, Daisuke Yamasaki, Kaneaki Tsuzaki

Materials Letters　228　273-276　2018/10/01

DOI： 10.1016/j.matlet.2018.06.022 　

ISSN： 1873-4979 0167-577X

Effect of state of carbon on fatigue properties and dislocation structure of Fe-0.017mass%C alloy Peer-reviewed

Nobuyuki Yoshimura, Kohsaku Ushioda, Yuichi Yoshida, Eisaku Sakurada, Mitsuharu Yonemura, Motomichi Koyama, Hiroshi Noguchi, Chihiro Watanabe

Materials Science and Engineering A　732　212-219　2018/08/08

DOI： 10.1016/j.msea.2018.06.082 　

ISSN： 0921-5093

Microstructural mechanisms of fatigue crack non-propagation in TRIP-maraging steels Peer-reviewed

Z. Zhang, M. Koyama, M. M. Wang, K. Tsuzaki, C. C. Tasan, H. Noguchi

International Journal of Fatigue　113　126-136　2018/08/01

DOI： 10.1016/j.ijfatigue.2018.04.013 　

ISSN： 0142-1123

Non-propagating fatigue cracks in austenitic steels with a micro-notch: Effects of dynamic strain aging, martensitic transformation, and microstructural hardness heterogeneity Peer-reviewed

Yuri Nishikura, Motomichi Koyama, Yusuke Yamamura, Takuro Ogawa, Kaneaki Tsuzaki, Hiroshi Noguchi

International Journal of Fatigue　113　359-366　2018/08/01

DOI： 10.1016/j.ijfatigue.2018.04.027 　

ISSN： 0142-1123

Ductile-to-brittle transition in tensile failure due to shear-affected zone with a stress-concentration source: a comparative study on punched-plate tensile-failure characteristics of precipitation-hardened and dual-phase steels Peer-reviewed

Hamada Shigeru, Zhang Jiwang, Zhang Kejin, Koyama Motomichi, Tsuchiyama Toshihiro, Yokoi Tatsuo, Noguchi Hiroshi

INTERNATIONAL JOURNAL OF FRACTURE　212　(2)　237-248　2018/08

DOI： 10.1007/s10704-018-0304-9 　

ISSN： 0376-9429

On the Utility of Crystal Plasticity Modeling to Uncover the Individual Roles of Microdeformation Mechanisms on the Work Hardening Response of Fe-23Mn-0.5C TWIP Steel in the Presence of Hydrogen

B. Bal, M. Koyama, D. Canadinc, G. Gerstein, H. J. Maier, K. Tsuzaki

Journal of Engineering Materials and Technology, Transactions of the ASME　140　(3)　2018/07/01

DOI： 10.1115/1.4038801 　

ISSN： 1528-8889 0094-4289

Comparative study of hydrogen embrittlement in stable and metastable high-entropy alloys Peer-reviewed

Kenshiro Ichii, Motomichi Koyama, Cemal Cem Tasan, Kaneaki Tsuzaki

Scripta Materialia　150　74-77　2018/06/01

DOI： 10.1016/j.scriptamat.2018.03.003 　

ISSN： 1359-6462

Temperature dependence of transgranular fatigue crack resistance in interstitial-free steel and Fe-C steels with supersaturated carbon: Effects of dynamic strain aging and dynamic precipitation Peer-reviewed

Bochuan Li, Motomichi Koyama, Eisaku Sakurada, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

International Journal of Fatigue　110　1-9　2018/05/01

DOI： 10.1016/j.ijfatigue.2018.01.003 　

ISSN： 0142-1123

Microstructural hardness heterogeneity triggers fatigue crack non-propagation in as-hot-rolled Fe-30Mn-3Si-3Al twinning-induced plasticity steel Peer-reviewed

Motomichi Koyama, Yusuke Yamamura, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

International Journal of Fatigue　108　18-24　2018/03/01

DOI： 10.1016/j.ijfatigue.2017.11.009 　

ISSN： 0142-1123

High-concentration carbon assists plasticity-driven hydrogen embrittlement in a Fe-high Mn steel with a relatively high stacking fault energy Peer-reviewed

Ibrahim Burkay Tuğluca, Motomichi Koyama, Burak Bal, Demircan Canadinc, Eiji Akiyama, Kaneaki Tsuzaki

Materials Science and Engineering A　717　78-84　2018/02/21

DOI： 10.1016/j.msea.2018.01.087 　

ISSN： 0921-5093

Micrographic Digital Image Correlation Coupled with Microlithography: Case Study of Strain Localization and Subsequent Cracking at an FIB Notch Tip in a Laminated Ti-6Al-4V Alloy

M. Koyama, Y. Tanaka, K. Tsuzaki

Experimental Mechanics　58　(2)　381-386　2018/02/01

DOI： 10.1007/s11340-017-0336-5 　

ISSN： 1741-2765 0014-4851

Hydrogen-assisted failure in a bimodal twinning-induced plasticity steel: Delamination events and damage evolution Peer-reviewed

Abbas Mohammadi, Motomichi Koyama, Gregory Gerstein, Hans Jürgen Maier, Hiroshi Noguchi

International Journal of Hydrogen Energy　43　(4)　2492-2502　2018/01/25

DOI： 10.1016/j.ijhydene.2017.11.177 　

ISSN： 0360-3199

Visualization of dislocations through electron channeling contrast imaging at fatigue crack tip, interacting with pre-existing dislocations

Kishan Habib, Motomichi Koyama, Toshihiro Tsuchiyama, Hiroshi Noguchi

Materials Research Letters　6　(1)　61-66　2018/01/02

DOI： 10.1080/21663831.2017.1392370 　

ISSN： 2166-3831

Influence of shear-affected-zone due to punching on tensile characteristics of steel plate

Kejin Zhang, Shigeru Hamada, Motomichi Koyama, Tatsuo Yokoi, Hiroshi Noguchi

Procedia Structural Integrity　13　1047-1052　2018/01/01

DOI： 10.1016/j.prostr.2018.12.196 　

Re-examination of fatigue crack propagation mechanism under cyclic Mode II loading

Shigeru Hamada, Taro Suemasu, Motomichi Koyama, Masaharu Ueda, Hiroshi Noguchi

Procedia Structural Integrity　13　1026-1031　2018/01/01

DOI： 10.1016/j.prostr.2018.12.191 　

Crystallographic orientation-dependent growth mode of microstructurally fatigue small crack in a laminated Ti-6Al-4V alloy

Akira Maenosono, Motomichi Koyama, Yoshihisa Tanaka, Shien Ri, Qinghu Wang, Hiroshi Noguchi

Procedia Structural Integrity　13　694-699　2018/01/01

DOI： 10.1016/j.prostr.2018.12.115 　

ISSN： 2452-3216

Optical microscopy-Based damage quantification: an example of cryogenic deformation of a dual-Phase steel

Nao Uehata, Motomichi Koyama, Shusaku Takagi, Kaneaki Tsuzaki

ISIJ International　58　(1)　179-185　2018

DOI： 10.2355/isijinternational.ISIJINT-2017-468 　

ISSN： 0915-1559

Proposal and verification of novel fatigue crack propagation simulation method by finite element method. Peer-reviewed

T. Sano, Motomichi Koyama, D. Sasaki, H. Noguchi

Structural Integrity Procedia　2018

Analysis of fatigue crack configuration influence on fatigue life. Peer-reviewed

M. Aibara, Motomichi Koyama, S. Hamada, H. Noguchi

Structural Integrity Procedia　2018

Quantification method for parameters affecting multi-scale roughness-induced fatigue crack closure. Peer-reviewed

T. Mizoguchi, Motomichi Koyama, H. Noguchi

Structural Integrity Procedia　2018

The influence of fracture surface contact in fatigue crack propagation of material having texture under Mode II loading. Peer-reviewed

T. Suemasu, Motomichi Koyama, S. Hamada, M. Ueda, H. Noguchi

Structural Integrity Porcedia　2018

Fatigue crack growth behavior and associated microstructure in a metastable high-entropy alloy. Peer-reviewed

T. Eguchi, Motomichi Koyama, Y. Fukushima, C.C. Tasan, Kaneaki Tsuzaki

Structural Integrity Procedia　2018

Strain rate sensitivity of microstructural damage evolution in a dual-phase steel pre-charged with hydrogen. Peer-reviewed

T. Kumamoto, Motomichi Koyama, Kaneaki Tsuzaki

Structural Integrity Procedia　2018

Localized plasticity and associated cracking in stable and metastable high-entropy alloys pre-charged with hydrogen. Peer-reviewed

K. Ichii, Motomichi Koyama, C.C. Tasan, Kaneaki Tsuzaki

Structural Integrity Procedia　2018

Small fatigue crack growth in a high entropy alloy. Peer-reviewed

K. Suzuki, Motomichi Koyama, H. Suzuki

Structural Integrity Procedia　2018

Proposal of fractographic analysis method coupled with EBSD and ECCI. Peer-reviewed

T. Kaida, Motomichi Koyama, S. Hamada, H. Noguchi, E. Sakurada, T. Yokoi, K. Ushioda

2018

Effect of Si on temperature dependence of non-propagation limit of small fatigue crack in a Fe-C alloy. Peer-reviewed

K. Kishida, Motomichi Koyama, N. Yoshimura, E. Sakurada, T. Yokoi, K. Ushioda, Kaneaki Tsuzaki, H. Noguchi

Structural Integrity Procedia　2018

A new design concept for prevention of hydrogen-induced mechanical degradation: viewpoints of metastability and high entropy. Peer-reviewed

Motomichi Koyama, T Eguchi, K. Ichii, Kaneaki Tsuzaki

Structural Integrity Procedia　2018

Cooling and deformation-induced hydrogen desorption in metastable austenitic steels detected by mass spectroscopy. Peer-reviewed

Motomichi Koyama, N. Terao, T. Hojo, E.Akiyama, Kaneaki Tsuzaki

Conference proceedings　J03　2018

Fatigue behavior of Fe-Cr-Ni-based metastable austenitic steels with an identical tensile strength and different solute carbon contents Peer-reviewed

Takuro Ogawa, Motomichi Koyama, Yuri Nishikura, Kaneaki Tsuzaki, Hiroshi Noguchi

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　104　(2)　88-97　2018

DOI： 10.2355/tetsutohagane.TETSU-2017-058 　

ISSN： 0021-1575

Influence of stress re-distribution on hydrogen-induced fatigue crack propagation Peer-reviewed

Daisuke SaSaki, Motomichi Koyama, Hiroshi Noguchi

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　104　(1)　46-53　2018

DOI： 10.2355/tetsutohagane.TETSU-2017-050 　

ISSN： 0021-1575

Interstitial carbon enhanced corrosion resistance of Fe-33Mn-xC austenitic steels: Inhibition of anodic dissolution Peer-reviewed

Aya Chiba, Motomichi Koyama, Eiji Akiyama, Toshiyasu Nishimura

Journal of the Electrochemical Society　165　(2)　C19-C26　2018

DOI： 10.1149/2.0661802jes 　

ISSN： 1945-7111 0013-4651

eISSN： 1945-7111

Split and Shift of epsilon-martensite Peak in an X-ray Diffraction Profile during Hydrogen Desorption: A Geometric Effect of Atomic Sequence Peer-reviewed

Koyama Motomichi, Abe Yuji, Tsuzaki Kaneaki

ISIJ INTERNATIONAL　58　(9)　1745-1747　2018

DOI： 10.2355/isijinternational.ISIJINT-2018-260 　

ISSN： 0915-1559

Microstructural damage evolution and arrest in binary Fe-high-Mn alloys with different deformation temperatures. Peer-reviewed

Motomichi Koyama, T. Kaneko, T. Sawaguchi, K. Tsuzaki

International Journal of Fracture　213　(2)　193-206　2018

DOI： 10.1007/s10704-018-0307-6 　

Room-temperature blue brittleness of Fe-Mn-C austenitic steels Peer-reviewed

Motomichi Koyama, Yusaku Shimomura, Aya Chiba, Eiji Akiyama, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　141　20-23　2017/12

DOI： 10.1016/j.scriptamat.2017.07.017 　

ISSN： 1359-6462

Reply to comments on the paper "In situ observations of silver-decoration evolution under hydrogen permeation: Effects of grain boundary misorientation on hydrogen flux in pure iron" by Gavriljuk and Teus Peer-reviewed

Motomichi Koyama, Daisuke Yamasaki, Kaneald Tsuzaki

SCRIPTA MATERIALIA　140　91-92　2017/11

DOI： 10.1016/j.scriptamat.2017.07.019 　

ISSN： 1359-6462

Fatigue crack non-propagation assisted by nitrogen-enhanced dislocation planarity in austenitic stainless steels Peer-reviewed

Kishan Habib, Motomichi Koyama, Toshihiro Tsuchiyama, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　104　158-170　2017/11

DOI： 10.1016/j.ijfatigue.2017.07.019 　

ISSN： 0142-1123

eISSN： 1879-3452

Effects of epsilon-martensitic transformation on crack tip deformation, plastic damage accumulation, and slip plane cracking associated with low-cycle fatigue crack growth Peer-reviewed

Yun-Byum Ju, Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　103　533-545　2017/10

DOI： 10.1016/j.ijfatigue.2017.06.040 　

ISSN： 0142-1123

eISSN： 1879-3452

Hydrogen desorption and cracking associated with martensitic transformation in Fe-Cr-Ni-Based austenitic steels with different carbon contents Peer-reviewed

Motomichi Koyama, Takuro Ogawa, Dingshun Yan, Yuya Matsumoto, Cemal Cem Tasan, Kenichi Takai, Kaneaki Tsuzaki

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　42　(42)　26423-26435　2017/10

DOI： 10.1016/j.ijhydene.2017.08.209 　

ISSN： 0360-3199

eISSN： 1879-3487

Micrographic Digital Image Correlation Coupled with Microlithography: Case Study of Strain Localization and Subsequent Cracking at an FIB Notch Tip in a Laminated Ti-6Al-4VAlloy Peer-reviewed

M. Koyama, Y. Tanaka, K. Tsuzaki

Experimental Mechanics　58　381-386　2017/09

Threshold stress intensity factor range of a mechanically-long and microstructually-short crack perpendicular to an interface with plastic mismatch Peer-reviewed

Bochuan Li, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

ENGINEERING FRACTURE MECHANICS　182　287-302　2017/09

DOI： 10.1016/j.engfracmech.2017.07.023 　

ISSN： 0013-7944

eISSN： 1873-7315

Material property controlling non-propagating fatigue crack length of mechanically and physically short-crack based on Dugdale-model analysis Peer-reviewed

Naoki Fukumura, Bochuan Li, Motomichi Koyama, Tomohiro Suzuki, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi

THEORETICAL AND APPLIED FRACTURE MECHANICS　90　193-202　2017/08

DOI： 10.1016/j.tafmec.2017.04.012 　

ISSN： 0167-8442

eISSN： 1872-7638

Effects of martensitic transformability and dynamic strain age hardenability on plasticity in metastable austenitic steels containing carbon Peer-reviewed

Takuro Ogawa, Motomichi Koyama, Cemal Cem Tasan, Kaneaki Tsuzaki, Hiroshi Noguchi

JOURNAL OF MATERIALS SCIENCE　52　(13)　7868-7882　2017/07

DOI： 10.1007/s10853-017-1052-3 　

ISSN： 0022-2461

eISSN： 1573-4803

Characteristics of hydrogen-assisted intergranular fatigue crack growth in interstitial-free steel: role of plastic strain localization Peer-reviewed

Motomichi Koyama, Yosuke Onishi, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FRACTURE　206　(1)　123-130　2017/07

DOI： 10.1007/s10704-017-0205-3 　

ISSN： 0376-9429

eISSN： 1573-2673

Effect of the state of carbon on ductility in Fe-0.017mass%C ferritic steel Peer-reviewed

Nobuyuki Yoshimura, Kohsaku Ushioda, Mitsuharu Yonemura, Motomichi Koyama, Masaki Tanaka, Hiroshi Noguchi

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　701　120-128　2017/07

DOI： 10.1016/j.msea.2017.06.070 　

ISSN： 0921-5093

eISSN： 1873-4936

Effects of lamella size and connectivity on fatigue crack resistance of TRIP-maraging steel

Z. Zhang, M. Koyama, M. M. Wang, K. Tsuzaki, C. C. Tasan, H. Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　100　176-186　2017/07

DOI： 10.1016/j.ijfatigue.2017.03.040 　

ISSN： 0142-1123

eISSN： 1879-3452

Impact of Mn-C couples on fatigue crack growth in austenitic steels: Is the attractive atomic interaction negative or positive? Peer-reviewed

Kishan Habib, Motomichi Koyama, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　99　1-12　2017/06

DOI： 10.1016/j.ijfatigue.2017.02.009 　

ISSN： 0142-1123

eISSN： 1879-3452

Multiscale in situ deformation experiments: A sequential process from strain localization to failure in a laminated Ti-6Al-4V alloy Peer-reviewed

Motomichi Koyama, Keita Yamanouchi, Qinghua Wang, Shien Ri, Yoshihisa Tanaka, Yasuaki Hamano, Shigeto Yamasaki, Masatoshi Mitsuhara, Masataka Ohkubo, Hiroshi Noguchi, Kaneaki Tsuzaki

MATERIALS CHARACTERIZATION　128　217-225　2017/06

DOI： 10.1016/j.matchar.2017.04.010 　

ISSN： 1044-5803

eISSN： 1873-4189

Two-dimensional Moire phase analysis for accurate strain distribution measurement and application in crack prediction Peer-reviewed

Qinghua Wang, Shien Ri, Hiroshi Tsuda, Motomichi Koyama, Kaneaki Tsuzaki

OPTICS EXPRESS　25　(12)　13465-13480　2017/06

DOI： 10.1364/OE.25.013465 　

ISSN： 1094-4087

Underlying interstitial carbon concentration dependence of transgranular fatigue crack resistance in Fe-C ferritic steels: The kinetic effect viewpoint Peer-reviewed

Bochuan Li, Motomichi Koyama, Eisaku Sakurada, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　98　101-110　2017/05

DOI： 10.1016/j.ijfatigue.2017.01.029 　

ISSN： 0142-1123

eISSN： 1879-3452

Interfacial hydrogen localization in austenite/martensite dual-phase steel visualized through optimized silver decoration and scanning Kelvin probe force microscopy Peer-reviewed

T. Nagashima, M. Koyama, A. Bashir, M. Rohwerder, C. C. Tasan, E. Akiyama, D. Raabe, K. Tsuzaki

MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION　68　(3)　306-310　2017/03

DOI： 10.1002/maco.201609104 　

ISSN： 0947-5117

eISSN： 1521-4176

In situ observations of silver-decoration evolution under hydrogen permeation: Effects of grain boundary misorientation on hydrogen flux in pure iron Peer-reviewed

Motomichi Koyama, Daisuke Yamasaki, Tatsuya Nagashima, Cemal Cem Tasan, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　129　48-51　2017/03

DOI： 10.1016/j.scriptamat.2016.10.027 　

ISSN： 1359-6462

Generalized evaluation method for determining transition crack length for microstructurally small to microstructurally large fatigue crack growth: Experimental definition, facilitation, and validation Peer-reviewed

Toshinobu Omura, Motomichi Koyama, Yasuaki Hamano, Kaneaki Tsuzaki, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　95　38-44　2017/02

DOI： 10.1016/j.ijfatigue.2016.10.010 　

ISSN： 0142-1123

eISSN： 1879-3452

Mechanical-probabilistic evaluation of size effect of fatigue life using data obtained from single smooth specimen: An example using Fe-30Mn-4Si-2Al seismic damper alloy Peer-reviewed

Motomichi Koyama, Huichao Li, Yasuaki Hamano, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

ENGINEERING FAILURE ANALYSIS　72　34-47　2017/02

DOI： 10.1016/j.engfailanal.2016.11.015 　

ISSN： 1350-6307

eISSN： 1873-1961

Study on crack occurrence of titanium alloy in tensile test by advanced moiré technique

Q. H. Wang, S. Ri, Y. Tanaka, K. Naito, M. Koyama, K. Tsuzaki, M. Ohkubo

ICF 2017 - 14th International Conference on Fracture　2　481-482　2017/01/01

Hydrogen embrittlement of binary high Mn austenitic steels

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

ICF 2017 - 14th International Conference on Fracture　1　75-76　2017/01/01

Visualization of strain concentrations in composites using advanced image processing techniques

Q. Wang, S. Ri, Y. Tanaka, M. Koyama

ICCM International Conferences on Composite Materials　2017-August　2017/01/01

Investigation on Mode I propagation behavior of fatigue crack in precipitation-hardened aluminum alloy with different Mg content

S. F. Anis, M. Koyama, H. Noguchi

Materials Science Forum　889　143-147　2017

DOI： 10.4028/www.scientific.net/MSF.889.143 　

ISSN： 0255-5476

Potential and Roles of Solute Carbon on Fatigue Resistance in Steels Peer-reviewed

56　(7)　458-461　2017

DOI： 10.2320/materia.56.458 　

ISSN： 1340-2625

Fe-Cフェライト二元合金におけるコーキシング効果発現因子： ひずみ時効現象に注目して Peer-reviewed

小山 元道, 任 博泓, 吉村 信幸, 桜田 栄作, 潮田 浩作, 野口 博司

鉄 と 鋼 Tetsu-to-Hagané　103　(11)　660-666　2017

Comparative study on small fatigue crack propagation between Fe-30Mn-3Si-3Al and Fe-23Mn-0.5C twinning-induced plasticity steels: Aspects of non-propagation of small fatigue cracks Peer-reviewed

Motomichi Koyama, Yusuke Yamamura, Rinqing Che, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　94　1-5　2017/01

DOI： 10.1016/j.ijfatigue.2016.09.003 　

ISSN： 0142-1123

eISSN： 1879-3452

Intrinsic Factors that Trigger the Coaxing Effect in Binary Fe-C Ferritic Alloys with a Focus on Strain Aging Peer-reviewed

Motomichi Koyama, Bohong Ren, Nobuyuki Yoshimura, Eisaku Sakurada, Kohsaku Ushioda, Hiroshi Noguchi

ISIJ INTERNATIONAL　57　(2)　358-364　2017

DOI： 10.2355/isijinternational.ISIJINT-2016-513 　

ISSN： 0915-1559

eISSN： 1347-5460

Recent progress in microstructural hydrogen mapping in steels: quantification, kinetic analysis, and multi-scale characterisation Peer-reviewed

Motomichi Koyama, Michael Rohwerder, Cemal Cem Tasan, Asif Bashir, Eiji Akiyama, Kenichi Takai, Dierk Raabe, Kaneaki Tsuzaki

MATERIALS SCIENCE AND TECHNOLOGY　33　(13)　1481-1496　2017

DOI： 10.1080/02670836.2017.1299276 　

ISSN： 0267-0836

eISSN： 1743-2847

Intrinsic Factors That Trigger the Coaxing Effect in Binary Fe-C Ferritic Alloys with a Focus on Strain Aging

Motomichi Koyama, Bohong Ren, Nobuyuki Yoshimura, Eisaku Sakurada, Kohsaku Ushioda, Hiroshi Noguchi

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　103　(11)　52-58　2017

DOI： 10.2355/tetsutohagane.TETSU-2017-043 　

ISSN： 0021-1575

eISSN： 1883-2954

Effect of strain rate on hydrogen embrittlement susceptibility of twinning-induced plasticity steel pre-charged with high-pressure hydrogen gas Peer-reviewed

B. Bal, M. Koyama, G. Gerstein, H. J. Maier, K. Tsuzaki

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　41　(34)　15362-15372　2016/09

DOI： 10.1016/j.ijhydene.2016.06.259 　

ISSN： 0360-3199

eISSN： 1879-3487

Martensitic transformation-induced hydrogen desorption characterized by utilizing cryogenic thermal desorption spectroscopy during cooling Peer-reviewed

Motomichi Koyama, Yuji Abe, Kei Saito, Eiji Akiyama, Kenichi Takai, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　122　50-53　2016/09

DOI： 10.1016/j.scriptamat.2016.05.012 　

ISSN： 1359-6462

Potential resistance to transgranular fatigue crack growth of Fe-C alloy with a supersaturated carbon clarified through FIB micro-notching technique Peer-reviewed

Bochuan Li, Motomichi Koyama, Eisaku Sakurada, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF FATIGUE　87　1-5　2016/06

DOI： 10.1016/j.ijfatigue.2016.01.003 　

ISSN： 0142-1123

eISSN： 1879-3452

Hydrogen Embrittlement Susceptibility of Fe-Mn Binary Alloys with High Mn Content: Effects of Stable and Metastable epsilon-Martensite, and Mn Concentration Peer-reviewed

Motomichi Koyama, Shota Okazaki, Takahiro Sawaguchi, Kaneaki Tsuzaki

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE　47A　(6)　2656-2673　2016/06

DOI： 10.1007/s11661-016-3431-9 　

ISSN： 1073-5623

eISSN： 1543-1940

In situ microscopic observations of low-cycle fatigue-crack propagation in high-Mn austenitic alloys with deformation-induced epsilon-martensitic transformation Peer-reviewed

Yun-Byum Ju, Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

ACTA MATERIALIA　112　326-336　2016/06

DOI： 10.1016/j.actamat.2016.04.042 　

ISSN： 1359-6454

eISSN： 1873-2453

Elucidation of the effects of cementite morphology on damage formation during monotonic and cyclic tension in binary low carbon steels using in situ characterization Peer-reviewed

Motomichi Koyama, Yachen Yu, Jia-Xi Zhou, Nobuyuki Yoshimura, Eisaku Sakurada, Kohsaku Ushioda, Hiroshi Noguchi

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　667　358-367　2016/06

DOI： 10.1016/j.msea.2016.05.029 　

ISSN： 0921-5093

eISSN： 1873-4936

Hexagonal close-packed Martensite-related Fatigue Crack Growth under the Influence of Hydrogen: Example of Fe-15Mn-10Cr-8Ni-4Si Austenitic Alloy Peer-reviewed

Kaneaki Tsuzaki, Koki Fukuda, Motomichi Koyama, Hisao Matsunaga

SCRIPTA MATERIALIA　113　6-9　2016/03

DOI： 10.1016/j.scriptamat.2015.10.016 　

ISSN： 1359-6462

Suppression effect of pearlite on hydrogen-assisted crack propagation

SASAKI Daisuke, KOYAMA Motomichi, NOGUCHI Hiroshi

The Proceedings of Mechanical Engineering Congress, Japan　2016　S0310404　2016

DOI： 10.1299/jsmemecj.2016.s0310404 　

eISSN： 2424-2667

Kinetics of Carbon Diffusion and Crystallography of Stacking Faults toward Understanding "Room Temperature" Strain Aging in Austenitic Steels Peer-reviewed

21　(4)　186-189　2016

ISSN： 1341-688X

Intergranular Fatigue Crack Initiation and its Associated Small Fatigue Crack Propagation in Water-quenched Fe-C Fully Ferritic Steel Peer-reviewed

Motomichi Koyama, Zhou-Jia Xi, Yuichi Yoshida, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　102　(5)　268-273　2016

DOI： 10.2355/tetsutohagane.TETSU-2015-108 　

ISSN： 0021-1575

eISSN： 1883-2954

Hydrogen-assisted damage in austenite/martensite dual-phase steel Peer-reviewed

Motomichi Koyama, Cemal Cem Tasan, Tatsuya Nagashima, Eiji Akiyama, Dierk Raabe, Kaneaki Tsuzaki

PHILOSOPHICAL MAGAZINE LETTERS　96　(1)　9-18　2016/01

DOI： 10.1080/09500839.2015.1130275 　

ISSN： 0950-0839

eISSN： 1362-3036

Combined Multi-scale Analyses on Strain/Damage/Microstructure in Steel: Example of Damage Evolution Associated with epsilon-martensitic Transformation Peer-reviewed

Takahiro Kaneko, Motomichi Koyama, Tomoya Fujisawa, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　102　(5)　227-236　2016

DOI： 10.2355/tetsutohagane.TETSU-2015-081 　

ISSN： 0021-1575

eISSN： 1883-2954

Characteristic Fatigue Crack Growth Behavior of Low Carbon Steel under Low-pressure Hydrogen Gas Atmosphere in an Ultra-low Frequency Peer-reviewed

Yosuke Onishi, Motomichi Koyama, Daisuke Sasaki, Hiroshi Noguchi

ISIJ INTERNATIONAL　56　(5)　855-860　2016

DOI： 10.2355/isijinternational.ISIJINT-2015-647 　

ISSN： 0915-1559

eISSN： 1347-5460

Notch Sensitivity of the Fatigue Limit in High-Strength Steel Peer-reviewed

Yasuaki Hamano, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

ISIJ INTERNATIONAL　56　(8)　1480-1486　2016

DOI： 10.2355/isijinternational.ISIJINT-2015-744 　

ISSN： 0915-1559

eISSN： 1347-5460

Suppression Mechanism of Strain-age-hardening in Carbon Steel Associated with Hydrogen Uptake Peer-reviewed

Takuro Ogawa, Motomichi Koyama, Hiroshi Noguchi

ISIJ INTERNATIONAL　56　(9)　1656-1661　2016

DOI： 10.2355/isijinternational.ISIJINT-2016-063 　

ISSN： 0915-1559

eISSN： 1347-5460

Combined Multi-scale Analyses on Strain/Damage/Microstructure in Steel: Example of Damage Evolution Associated with epsilon-martensitic Transformation Peer-reviewed

Takahiro Kaneko, Motomichi Koyama, Tomoya Fujisawa, Kaneaki TsuzakI'

ISIJ INTERNATIONAL　56　(11)　2037-2046　2016

DOI： 10.2355/isijinternational.ISIJINT-2016-272 　

ISSN： 0915-1559

eISSN： 1347-5460

Enhancing Hydrogen Embrittlement Resistance of Lath Martensite by Introducing Nano-Films of Interlath Austenite Peer-reviewed

Meimei Wang, C. Cem Tasan, Motomichi Koyama, Dirk Ponge, Dierk Raabe

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE　46A　(9)　3797-3802　2015/09

DOI： 10.1007/s11661-015-3009-y 　

ISSN： 1073-5623

eISSN： 1543-1940

Positive and negative effects of hydrogen on tensile behavior in polycrystalline Fe-30Mn-(6-x)Si-xAl austenitic alloys Peer-reviewed

Kensuke Yamada, Motomichi Koyama, Takahiro Kaneko, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　105　54-57　2015/08

DOI： 10.1016/j.scriptamat.2015.05.007 　

ISSN： 1359-6462

Effects of hydrogen-altered yielding and work hardening on plastic-zone evolution: A finite-element analysis Peer-reviewed

Daisuke Sasaki, Motomichi Koyama, Kenji Higashida, Kaneaki Tsuzaki, Hiroshi Noguchi

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　40　(31)　9825-9837　2015/08

DOI： 10.1016/j.ijhydene.2015.05.187 　

ISSN： 0360-3199

eISSN： 1879-3487

Factors affecting hydrogen-assisted cracking in a commercial tempered martensitic steel: Mn segregation, MnS, and the stress state around abnormal cracks Peer-reviewed

Daisuke Sasaki, Motomichi Koyama, Hiroshi Noguchi

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　640　72-81　2015/07

DOI： 10.1016/j.msea.2015.05.083 　

ISSN： 0921-5093

eISSN： 1873-4936

Effects of cementite morphology on short-fatigue-crack propagation in binary Fe-C steel Peer-reviewed

Zhou-Jia Xi, Motomichi Koyama, Yuichi Yoshida, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

PHILOSOPHICAL MAGAZINE LETTERS　95　(7)　384-391　2015/07

DOI： 10.1080/09500839.2015.1076174 　

ISSN： 0950-0839

eISSN： 1362-3036

Importance of crack-propagation-induced epsilon-martensite in strain-controlled low-cycle fatigue of high-Mn austenitic steel Peer-reviewed

Huichao Li, Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki, Hiroshi Noguchi

PHILOSOPHICAL MAGAZINE LETTERS　95　(6)　303-311　2015/06

DOI： 10.1080/09500839.2015.1052029 　

ISSN： 0950-0839

eISSN： 1362-3036

Tensile properties of precracked tempered martensitic steel specimens tested at ultralow strain rates in high-pressure hydrogen atmosphere Peer-reviewed

Daisuke Sasaki, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

PHILOSOPHICAL MAGAZINE LETTERS　95　(5)　260-268　2015/05

DOI： 10.1080/09500839.2015.1049574 　

ISSN： 0950-0839

eISSN： 1362-3036

An Overview of Dual-Phase Steels: Advances in Microstructure-Oriented Processing and Micromechanically Guided Design Peer-reviewed

C. C. Tasan, M. Diehl, D. Yan, M. Bechtold, F. Roters, L. Schemmann, C. Zheng, N. Peranio, D. Ponge, M. Koyama, K. Tsuzaki, D. Raabe

ANNUAL REVIEW OF MATERIALS RESEARCH, VOL 45　45　391-431　2015

DOI： 10.1146/annurev-matsci-070214-021103 　

ISSN： 1531-7331

Influences of ε martensite and Mn concentration o hydrogen uptake and desorption in Fe-high Mn vinary alloys by cryogenic thermal desorption analysis. Peer-reviewed

Motomichi Koyama, Kaneaki Tsuzaki

ISIJ Intrenational　55　2269-2271　2015

Effects of Si on Tensile Properties Associated with Deformation-Induced epsilon-Martensitic Transformation in High Mn Austenitic Alloys Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

JOURNAL OF THE JAPAN INSTITUTE OF METALS　79　(12)　657-663　2015

DOI： 10.2320/jinstmet.J2015047 　

ISSN： 0021-4876

eISSN： 1880-6880

Notch Sensitivity in Fatigue Limit of High Strength Steel Peer-reviewed

Yasuaki Hamano, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　101　(10)　552-558　2015

DOI： 10.2355/tetsutohagane.TETSU-2015-045 　

ISSN： 0021-1575

eISSN： 1883-2954

Suppression Mechanism of Strain-age Hardening in Carbon Steel Associated with Hydrogen Uptake Peer-reviewed

Takuro Ogawa, Motomichi Koyama, Hiroshi Noguchi

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　101　(10)　546-551　2015

DOI： 10.2355/tetsutohagane.TETSU-2015-033 　

ISSN： 0021-1575

eISSN： 1883-2954

Detection of Charged Hydrogen in Ferritic Steel through Cryogenic Secondary Ion Mass Spectrometry Peer-reviewed

Atsushi Nishimoto, Motomichi Koyama, Shigeru Yamato, Yasuji Oda, Tohru Awane, Hiroshi Noguchi

ISIJ INTERNATIONAL　55　(1)　335-337　2015

DOI： 10.2355/isijinternational.55.335 　

ISSN： 0915-1559

eISSN： 1347-5460

Effects of Si on Tensile Properties Associated with Deformation-Induced epsilon-Martensitic Transformation in High Mn Austenitic Alloys Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

MATERIALS TRANSACTIONS　56　(6)　819-825　2015

DOI： 10.2320/matertrans.M2015042 　

ISSN： 1345-9678

eISSN： 1347-5320

Deformation Twinning Behavior of Twinning-induced Plasticity Steels with Different Carbon Concentrations - Part 1: Atomic Force Microscopy and Electron Backscatter Diffraction Measurements Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　55　(8)　1747-1753　2015

DOI： 10.2355/isijinternational.ISIJINT-2015-069 　

ISSN： 0915-1559

eISSN： 1347-5460

Deformation Twinning Behavior of Twinning-induced Plasticity Steels with Different Carbon Concentrations - Part 2: Proposal of Dynamic-strain-aging-assisted Deformation Twinning Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　55　(8)　1754-1761　2015

DOI： 10.2355/isijinternational.ISIJINT-2015-070 　

ISSN： 0915-1559

eISSN： 1347-5460

Spatially and Kinetically Resolved Mapping of Hydrogen in a Twinning-Induced Plasticity Steel by Use of Scanning Kelvin Probe Force Microscopy Peer-reviewed

Motomichi Koyama, Asif Bashir, Michael Rohwerder, Sergiy V. Merzlikin, Eiji Akiyama, Kaneaki Tsuzaki, Dierk Raabe

JOURNAL OF THE ELECTROCHEMICAL SOCIETY　162　(12)　C638-C647　2015

DOI： 10.1149/2.0131512jes 　

ISSN： 0013-4651

eISSN： 1945-7111

epsilon -&gt;gamma Reverse Transformation-induced Hydrogen Desorption and Mn Effect on Hydrogen Uptake in Fe-Mn Binary Alloys Peer-reviewed

Motomichi Koyama, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　55　(10)　2269-2271　2015

DOI： 10.2355/isijinternational.ISIJINT-2015-215 　

ISSN： 0915-1559

eISSN： 1347-5460

Characteristic Fatigue Crack Growth Behavior of Low Carbon Steel Under Low-pressure Hydrogen Gas Atmosphere Peer-reviewed

Yosuke Ohnishi, Motomichi Koyama, Daisuke Sasaki, Hiroshi Noguchi

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　101　(11)　605-610　2015

DOI： 10.2355/tetsutohagane.TETSU-2015-018 　

ISSN： 0021-1575

eISSN： 1883-2954

Intergranular Fatigue Crack Initiation and Its Associated Small Fatigue Crack Propagation in Water-quenched Fe-C Fully Ferritic Steel Peer-reviewed

Motomichi Koyama, Zhou-Jia Xi, Yuichi Yoshida, Nobuyuki Yoshimura, Kohsaku Ushioda, Hiroshi Noguchi

ISIJ INTERNATIONAL　55　(11)　2463-2468　2015

DOI： 10.2355/isijinternational.ISIJINT-2015-305 　

ISSN： 0915-1559

eISSN： 1347-5460

Strain mapping with high spatial resolution across a wide observation range by digital image correlation on plastic replicas Peer-reviewed

Shigeru Hamada, Tomoya Fujisawa, Motomichi Koyama, Norimitsu Koga, Nobuo Nakada, Toshihiro Tsuchiyama, Masaharu Ueda, Hiroshi Noguchi

MATERIALS CHARACTERIZATION　98　140-146　2014/12

DOI： 10.1016/j.matchar.2014.10.010 　

ISSN： 1044-5803

eISSN： 1873-4189

Alloy Design, Combinatorial Synthesis, and Microstructure-Property Relations for Low-Density Fe-Mn-Al-C Austenitic Steels Peer-reviewed

D. Raabe, H. Springer, I. Gutierrez-Urrutia, F. Roters, M. Bausch, J. -B. Seol, M. Koyama, P. -P. Choi, K. Tsuzaki

JOM　66　(9)　1845-1856　2014/09

DOI： 10.1007/s11837-014-1032-x 　

ISSN： 1047-4838

eISSN： 1543-1851

Hydrogen-assisted decohesion and localized plasticity in dual-phase steel Peer-reviewed

Motomichi Koyama, Cemal Cem Tasan, Eiji Akiyama, Kaneaki Tsuzaki, Dierk Raabe

ACTA MATERIALIA　70　174-187　2014/05

DOI： 10.1016/j.actamat.2014.01.048 　

ISSN： 1359-6454

eISSN： 1873-2453

Hydrogen embrittlement associated with strain localization in a precipitation-hardened Fe-Mn-Al-C light weight austenitic steel Peer-reviewed

Motomichi Koyama, Hauke Springer, Sergiy V. Merzlikin, Kaneaki Tsuzaki, Eiji Akiyama, Dierk Raabe

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY　39　(9)　4634-4646　2014/03

DOI： 10.1016/j.ijhydene.2013.12.171 　

ISSN： 0360-3199

eISSN： 1879-3487

Factors affecting hydrogen embrittlement susceptibility of twinning-induced plasticity steels. Peer-reviewed

Motomichi Koyama, E. Akiyama, D. Raabe, Kaneaki Tsuzaki

Proc. 2nd HMnS　2014

Deformation Twinning Behavior of Twinning-Induced Plasticity Steels with Different Carbon Concentrations-Part 2: Proposal of Dynamic Strain Aging-Assisted Deformation Twinning- Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　100　(10)　1253-1260　2014

DOI： 10.2355/tetsutohagane.100.1253 　

ISSN： 0021-1575

eISSN： 1883-2954

Deformation Twinning Behavior of Twinning-Induced Plasticity Steels with Different Carbon Concentrations-Part 1: Analyses by Atomic Force Microscopy and Electron Backscatter Diffraction Measurements- Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　100　(10)　1246-1252　2014

DOI： 10.2355/tetsutohagane.100.1246 　

ISSN： 0021-1575

eISSN： 1883-2954

Fe-Mn-C-Al TWIP鋼の水素脆化における静的および動的ひずみ時効の影響 Peer-reviewed

小山元道, 秋山英二, 津﨑兼彰

鉄と鋼　100　1132-1139　2014

Fe-Mn-C TWIP鋼における室温動的ひずみ時効の影響因子 Peer-reviewed

小山元道, 秋山英二, 津﨑兼彰

鉄と鋼　100　1123-1131　2014

水素チャージ下引張試験におけるAl添加型TWIP鋼の水素脆化 Peer-reviewed

小山元道, 秋山英二, 津﨑兼彰

鉄と鋼　100　662-667　2014

Tensile Testing with Cyclic Strain Holding to Analyze Dynamic Recrystallization of Pure Lead Peer-reviewed

Muramatsu, Mayu, Koyama, Motomichi, Watanabe, Ikumu

ADVANCES IN MATERIALS SCIENCE AND ENGINEERING　2014　2014

DOI： 10.1155/2014/498674 　

ISSN： 1687-8434

eISSN： 1687-8442

Effects of Static and Dynamic Strain Aging on Hydrogen Embrittlement in TWIP Steels Containing Al

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　100　(9)　1132-1139　2014

DOI： 10.2355/tetsutohagane.100.1132 　

ISSN： 0021-1575

eISSN： 1883-2954

Factors Affecting Static Strain Aging Under Stress at Room Temperature in a Fe-Mn-C Twinning-Induced Plasticity Steel

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　100　(9)　1123-1131　2014

DOI： 10.2355/tetsutohagane.100.1123 　

ISSN： 0021-1575

eISSN： 1883-2954

Hydrogen Embrittlement in Al-Added Twinning-Induced Plasticity Steels Evaluated by Tensile Tests during Hydrogen Charging

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN　100　(5)　70-75　2014

DOI： 10.2355/tetsutohagane.100.662 　

ISSN： 0021-1575

eISSN： 1883-2954

Microstructure characteristic and its effect on mechanical and shape memory properties in a Fe-17Mn-8Si-0.3C alloy Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

JOURNAL OF ALLOYS AND COMPOUNDS　573　15-19　2013/10

DOI： 10.1016/j.jallcom.2013.03.289 　

ISSN： 0925-8388

eISSN： 1873-4669

Hydrogen-assisted quasi-cleavage fracture in a single crystalline type 316 austenitic stainless steel Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Takahiro Sawaguchi, Kazuyuki Ogawa, Irina V. Kireeva, Yury I. Chumlyakov, Kaneaki Tsuzaki

CORROSION SCIENCE　75　345-353　2013/10

DOI： 10.1016/j.corsci.2013.06.018 　

ISSN： 0010-938X

eISSN： 1879-0496

Hydrogen-assisted failure in a twinning-induced plasticity steel studied under in situ hydrogen charging by electron channeling contrast imaging Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki, Dierk Raabe

ACTA MATERIALIA　61　(12)　4607-4618　2013/07

DOI： 10.1016/j.actamat.2013.04.030 　

ISSN： 1359-6454

TWIP Effect and Plastic Instability Condition in an Fe-Mn-C Austenitic Steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　53　(2)　323-329　2013

DOI： 10.2355/isijinternational.53.323 　

ISSN： 0915-1559

eISSN： 1347-5460

Grain refinement effect on cryogenic tensile ductility in a Fe-Mn-C twinning-induced plasticity steel Peer-reviewed

Motomichi Koyama, Taekyung Lee, Chong Soo Lee, Kaneaki Tsuzaki

Materials and Design　49　234-241　2013

DOI： 10.1016/j.matdes.2013.01.061 　

ISSN： 1873-4197 0261-3069

Factors Affecting Static Strain Aging under Stress at Room Temperature in a Fe-Mn-C Twinning-induced Plasticity Steel Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　53　(6)　1089-1096　2013

DOI： 10.2355/isijinternational.53.1089 　

ISSN： 0915-1559

Effects of static and dynamic strain aging on hydrogen embrittlement in twip steels containing al Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

ISIJ International　53　(7)　1268-1274　2013

DOI： 10.2355/isijinternational.53.1268 　

ISSN： 0915-1559

Premature Fracture Mechanism in an Fe-Mn-C Austenitic Steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE　43A　(11)　4063-4074　2012/11

DOI： 10.1007/s11661-012-1220-7 　

ISSN： 1073-5623

eISSN： 1543-1940

Effect of deformation temperature on tensile properties in a pre-cooled Fe-Mn-C austenitic steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　556　331-336　2012/10

DOI： 10.1016/j.msea.2012.06.095 　

ISSN： 0921-5093

eISSN： 1873-4936

Hydrogen-induced delayed fracture of a Fe-22Mn-0.6C steel pre-strained at different strain rates Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　66　(11)　947-950　2012/06

DOI： 10.1016/j.scriptamat.2012.02.040 　

ISSN： 1359-6462

Effect of hydrogen content on the embrittlement in a Fe-Mn-C twinning-induced plasticity steel Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

CORROSION SCIENCE　59　277-281　2012/06

DOI： 10.1016/j.corsci.2012.03.009 　

ISSN： 0010-938X

Tensile deformation behavior of Fe-Mn-C TWIP steel with ultrafine elongated grain structure Peer-reviewed

Taekyung Lee, Motomichi Koyama, Kaneaki Tsuzaki, You-Hwan Lee, Chong Soo Lee

MATERIALS LETTERS　75　169-171　2012/05

DOI： 10.1016/j.matlet.2012.02.012 　

ISSN： 0167-577X

Hydrogen-induced cracking at grain and twin boundaries in an Fe-Mn-C austenitic steel Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Takahiro Sawaguchi, Dierk Raabe, Kaneaki Tsuzaki

SCRIPTA MATERIALIA　66　(7)　459-462　2012/04

DOI： 10.1016/j.scriptamat.2011.12.015 　

ISSN： 1359-6462

Influence of Dislocation Separation on Dynamic Strain Aging in a Fe-Mn-C Austenitic Steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

MATERIALS TRANSACTIONS　53　(3)　546-552　2012/03

DOI： 10.2320/matertrans.M2011342 　

ISSN： 1345-9678

eISSN： 1347-5320

TWIP effect and plastic instability condition in an Fe-Mn-C austenitic steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan　98　(6)　229-236　2012

DOI： 10.2355/tetsutohagane.98.229 　

ISSN： 0021-1575

Hydrogen embrittlement in a Fe-Mn-C ternary twinning-induced plasticity steel Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

CORROSION SCIENCE　54　1-4　2012/01

DOI： 10.1016/j.corsci.2011.09.022 　

ISSN： 0010-938X

Quasi-cleavage Fracture along Annealing Twin Boundaries in a Fe-Mn-C Austenitic Steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　52　(1)　161-163　2012

DOI： 10.2355/isijinternational.52.161 　

ISSN： 0915-1559

Inverse grain size dependence of critical strain for serrated flow in a Fe-Mn-C twinning-induced plasticity steel Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

PHILOSOPHICAL MAGAZINE LETTERS　92　(3)　145-152　2012

DOI： 10.1080/09500839.2011.640645 　

ISSN： 0950-0839

Selective appearance of epsilon-martensitic transformation and dynamic strain aging in Fe-Mn-C austenitic steels Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kaneaki Tsuzaki

PHILOSOPHICAL MAGAZINE　92　(24)　3051-3063　2012

DOI： 10.1080/14786435.2012.685769 　

ISSN： 1478-6435

eISSN： 1478-6443

Hydrogen Embrittlement in Al-added Twinning-induced Plasticity Steels Evaluated by Tensile Tests during Hydrogen Charging Peer-reviewed

Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki

ISIJ INTERNATIONAL　52　(12)　2283-2287　2012

DOI： 10.2355/isijinternational.52.2283 　

ISSN： 0915-1559

eISSN： 1347-5460

Work hardening and uniform elongation of an ultrafine-grained Fe-33Mn binary alloy Peer-reviewed

M. Koyama, T. Sawaguchi, K. Tsuzaki

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　530　659-663　2011/12

DOI： 10.1016/j.msea.2011.10.038 　

ISSN： 0921-5093

Nanoindentation/atomic force microscopy analyses of epsilon-martensitic transformation and shape memory effect in Fe-28Mn-6Si-5Cr alloy Peer-reviewed

K. Sekido, T. Ohmura, T. Sawaguchi, M. Koyama, H. W. Park, K. Tsuzaki

SCRIPTA MATERIALIA　65　(11)　942-945　2011/12

DOI： 10.1016/j.scriptamat.2011.08.010 　

ISSN： 1359-6462

Work hardening associated with epsilon-martensitic transformation, deformation twinning and dynamic strain aging in Fe-17Mn-0.6C and Fe-17Mn-0.8C TWIP steels Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Taekyung Lee, Chong Soo Lee, Kaneaki Tsuzaki

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　528　(24)　7310-7316　2011/09

DOI： 10.1016/j.msea.2011.06.011 　

ISSN： 0921-5093

Si content dependence on shape memory and tensile properties in Fe-Mn-Si-C alloys Peer-reviewed

M. Koyama, T. Sawaguchi, K. Tsuzaki

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　528　(6)　2882-2888　2011/03

DOI： 10.1016/j.msea.2010.12.065 　

ISSN： 0921-5093

Effect of deformation temperature on work hardening behavior in Fe-17Mn-0.6C and Fe-17Mn-0.8C steels. Peer-reviewed

Motomichi Koyama, T. Sawaguchi, Kaneaki Tsuzaki

Proceedings of HMnS　2011

Continuous Transition of Deformation Modes in Fe-30Mn-5Si-1Al Alloy Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kazuyuki Ogawa, Takehiko Kikuchi, Masato Murakami

MATERIALS TRANSACTIONS　51　(7)　1194-1199　2010/07

DOI： 10.2320/matertrans.M2010073 　

ISSN： 1345-9678

eISSN： 1347-5320

The improvement of shape recovery property through training treatment in an Fe-30Mn-5Si-1Al

M. Koyama, T. Sawaguchi, K. Ogawa, T. Kikuchi, M. Murakami

Proceedings of the International Conference on Martensitic Transformations, ICOMAT-08　583-586　2009/12/01

Continuous Transition of Deformation Mode in Fe-30Mn-5Si-1Al Alloy Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kazuyuki Ogawa, Takehiko Kikuchi, Masato Murakami

JOURNAL OF THE JAPAN INSTITUTE OF METALS　73　(3)　174-179　2009/03

DOI： 10.2320/jinstmet.73.174 　

ISSN： 0021-4876

eISSN： 1880-6880

Role of Si on the shape memory property of Fe-Mn-Si-C based alloys Peer-reviewed

M. Koyama, T. Sawaguchi, M. Murakami, K. Tsuzaki

ESOMAT 2009 - 8TH EUROPEAN SYMPOSIUM ON MARTENSITIC TRANSFORMATIONS　02015　2009

DOI： 10.1051/esomat/200902015 　

The effects of thermomechanical training treatment on the deformation characteristics of Fe-Mn-Si-Al alloys Peer-reviewed

Motomichi Koyama, Takahiro Sawaguchi, Kazuyuki Ogawa, Takehiko Kikuchi, Masato Murakami

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING　497　(1-2)　353-357　2008/12

DOI： 10.1016/j.msea.2008.07.026 　

ISSN： 0921-5093

Mechanism of reversible transformation-induced plasticity of Fe-Mn-Si shape memory alloys Peer-reviewed

Takahiro Sawaguchi, Leandru-Gheorghe Bujoreanu, Takehiko Kikuchi, Kazuyuki Ogawa, Motomichi Koyama, Masato Murakami

SCRIPTA MATERIALIA　59　(8)　826-829　2008/10

DOI： 10.1016/j.scriptamat.2008.06.030 　

ISSN： 1359-6462

AFM observation of microstructural changes in Fe-Mn-Si-Al shape memory alloy Peer-reviewed

Motomichi Koyama, Masato Murakami, Kazuyuki Ogawa, Takehiko Kikuchi, Takahiro Sawaguchi

MATERIALS TRANSACTIONS　49　(4)　812-816　2008/04

DOI： 10.2320/matertrans.MRA2007321 　

ISSN： 1345-9678

eISSN： 1347-5320

INFLUENCE OF AL CONCENTRATION ON DEFORMATION BEHAVIOR AND FRACTURE MODE OF FE-30MN-6(SI, AL) ALLOYS Peer-reviewed

K. Ogawa, T. Sawaguchi, T. Kikuchi, M. Koyama, M. Murakami

SMST-2007: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON SHAPE MEMORY AND SUPERELASTIC TECHNOLOGIES　645-+　2008

DOI： 10.1361/cp2007smst645 　

Shape memory characteristics of Fe-30Mn-5Si-lAl and Fe-28Mn-5Si-1A1-5Cr alloys Peer-reviewed

M. Koyama, M. Murakami, K. Ogawa, T. Kikuchi, S. Sawaguchi

SMST-2007: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON SHAPE MEMORY AND SUPERELASTIC TECHNOLOGIES　653-+　2008

DOI： 10.1361/cp2007smst653 　

Influence of Al on shape memory effect and twinning induced plasticity of Fe-Mn-Si-Al system alloy Peer-reviewed

Motomichi Koyama, Masato Murakami, Kazuyuki Ogawa, Takehiko Kikuchi, Takahiro Sawaguchi

MATERIALS TRANSACTIONS　48　(10)　2729-2734　2007/10

DOI： 10.2320/matertrans.MRA2007124 　

ISSN： 1345-9678

eISSN： 1347-5320

Atomic force microscopic observation of microstructural changes in Fe-Mn-Si-Al shape memory alloy Peer-reviewed

Motomichi Koyama, Masato Murakami, Kazuyuki Ogawa, Takehiko Kikuchi, Takahiro Sawaguchi

JOURNAL OF THE JAPAN INSTITUTE OF METALS　71　(9)　672-677　2007/09

DOI： 10.2320/jinstmet.71.672 　

ISSN： 0021-4876

eISSN： 1880-6880

Influence of Al on shape memory effect and twinning induced plasticity of Fe-Mn-Si-Al system alloy Peer-reviewed

Motomichi Koyama, Masato Murakami, Kazuyuki Ogawa, Takehiko Kikuchi, Takahiro Sawaguchi

JOURNAL OF THE JAPAN INSTITUTE OF METALS　71　(6)　502-507　2007/06

DOI： 10.2320/jinstmet.71.502 　

ISSN： 0021-4876

eISSN： 1880-6880