Research Career 【 display / non-display 】

Research Career 【 display / non-display 】

• Process and Materials Design in alloys

  The Other Research Programs  

  Project Year：  -   

• Deformation and Fracture of Steels

  Project Year：  -   

• Deformation and Farcture of Titanium Alloys

  Grant-in-Aid for Scientific Research  

  Project Year：  -   

Books 【 display / non-display 】

Books 【 display / non-display 】

• Handbook of Ecomaterials

  Yoshikazu Shinohara and Osamu Umezawa (Part： Contributor )

  Springer International Publishing  2019 ISBN: 978-3-319-68254-9

• Handbook of Ecomaterials

  Osamu Umezawa, Yoshikazu Shinohara, and Kohmei Halada (Part： Contributor )

  Springer International Publishing  2019 ISBN: 978-3-319-68255-6

• Standard Microstructures Group 1: Carbon steel & cast irons

  Materials Technology Education Association (Part： Supervisor )

  Yamamoto Scientific Tool Laboratory  2018.06

• Metal, Ceramic and Polymeric Composites for Various Uses

  John Cuppoletti ed. (Part： Joint Work , Range: Ch 4: Thermo-mechanical Treatment of Glass-balloon-dispersed Metal Matrix Composite )

  INTECH  2011.07 ISBN: 978-953-307-3

• Automotive Engineering: Lightweight, Functional, and Novel Materials (Series in Material Science and Engineering)

  Osamu Umezawa (Part： Joint Work )

  Taylor & Francis  2008.02 ISBN: 978-075031001

Papers 【 display / non-display 】

Papers 【 display / non-display 】

• Mechanism of Texture and Microstructure Evolution during High Temperature Plane Strain Compression in AZ31B and AZ80 Magnesium Alloys with Various Initial Textures

  Fukutomi Hiroshi, Park Hyung-Gyun, Kim Kwon-Hoo, Okayasu Kazuto, Hasegawa Makoto, Umezawa Osamu

  Journal of the Japan Institute of Metals and Materials ( The Japan Institute of Metals and Materials )  83 ( 8 )   264 - 272   2019.08  [Refereed]

  Joint Work

  　View Summary

  <p>The effects of pre-existent textures on the evolution behaviors of microstructure and texture at high-temperature plane strain compression deformation of AZ31B magnesium alloy have been studied. Deformation is conducted at 723 K with a strain rate of 5.0 × 10⁻² s⁻¹, up to −1.3 in true strain. When non-basal slip systems are the primary slip systems, {11<span style="text-decoration: overline;">2</span>0}<10<span style="text-decoration: overline;">1</span>0> texture develops. In this case, repeated change in microstructure and texture which was found in the previous work appeared with increasing strain. Namely, replacement of {11<span style="text-decoration: overline;">2</span>0}<10<span style="text-decoration: overline;">1</span>0> texture with {10<span style="text-decoration: overline;">1</span>0}<11<span style="text-decoration: overline;">2</span>0> texture and the reverse phenomenon occurs. While the {11<span style="text-decoration: overline;">2</span>0}<10<span style="text-decoration: overline;">1</span>0> oriented grains are small and with wavy shaped grain boundaries, the {10<span style="text-decoration: overline;">1</span>0}<11<span style="text-decoration: overline;">2</span>0> oriented grains are large and with rather straight grain boundaries. The mechanism of repeated change in microstructure and texture is discussed on the basis of preferential dynamic grain growth mechanism proposed by the authors.</p>

  DOI CiNii

• Effect of pearlite volume fraction on two-step ductile to brittle transition in ferrite + pearlite structure steel sheets

  Hiroyuki Kawata, Osamu Umezawa

  ISIJ International ( 一般社団法人 日本鉄鋼協会 )  59 ( 7 )   1344 - 1353   2019.07  [Refereed]

  Joint Work

  　View Summary

  <p>Multi structural steels exhibit high strength and good formability; however, their performance depends on the volume fraction of the secondary phase. In our previous study, ferrite + pearlite structural steel sheet showed the characteristic two-step ductile-to-brittle transition (DBT) with decreasing temperature, and the absorbed energy curve exhibited a distinct middle shelf. In this study, we evaluated the effect of pearlite volume fraction (<i>V</i>_P) on the DBT behavior by the Charpy impact test with sub-size specimens. For specimens without pearlite, the absorbed energy directly dropped from the upper shelf to the lower shelf with decreasing temperature. For samples with 2–3% pearlite, the absorbed energy corresponding to the transition temperature range was dispersed between the two shelves, and the transition behavior seemed to be the typical DBT behavior. When <i>V</i>_P was increased to 21%, the absorbed energy just above the transition-finish temperature became stable at a middle level between the two shelves; thus, the existence of a distinct middle shelf was confirmed. Although the transition-start temperature increased with increasing <i>V</i>_P, <i>V</i>_P did not affect the transition-finish temperature and the absorbed energy at the middle shelf. These results were analyzed with a simple model based on the Yoffee diagram.</p>

  DOI CiNii

• Crystal orientation analysis on stress corrosion cracking facets in austenitic stainless steels

  Ryo Wakinaga, Norimitsu Koga, Osamu Umezawa, Motoaki Morita, Shinichi Motoda, Tadashi Shinohara

  Key Engineering Materials   810   64 - 69   2019.07  [Refereed]  [Invited]

  Joint Work

  DOI

• Crystal lattice rotation and fatigue crack generation in aluminum wire under cyclic bending deformation

  Hayato Iketani, Osamu Umezawa, Hiroshi Fukutomi

    69 ( 6 )   302 - 308   2019.06  [Refereed]

  Joint Work

• A Subsurface fatigue crack generation model in near alpha titanium at low temperature

  Osamu Umezawa, Weibo Li

  Materials Science Forum   941   1336 - 1341   2018.12  [Refereed]  [Invited]

  Joint Work

  DOI

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Review Papers 【 display / non-display 】

Review Papers 【 display / non-display 】

• A Review of Subsurface Crack Initiation Models in High-cycle Fatigue for Titanium Alloys

  Weibo Li, Osamu Umezawa

  Key Engineering Materials   741   76 - 81   2017.06  [Refereed]  [Invited]

  Introduction and explanation (international conference proceedings)   Joint Work

  DOI

• Visualization of strain distribution on deformed steels using digital image correlation method

  Norimitsu Koga, Osamu Umezawa

  Key Engineering Materials   741   138 - 143   2017.06  [Refereed]  [Invited]

  Introduction and explanation (international conference proceedings)   Joint Work

  DOI

• Critical experiments and analyses at cryogenic temperature to promote a better understanding of mechanical properties in high-strength alloys

  Osamu Umezawa, Kotobu Nagai

  Advances in Cryogenic Engineering-Materials   60   327 - 332   2014.01  [Refereed]  [Invited]

  Introduction and explanation (scientific journal)   Joint Work

  　View Summary

  合金の変形およびき裂形成の金属組織学的検討における極低温環境の有用性について解説した。極低温ではひずみ速度依存性が高まり、内部疲労き裂発生は明瞭かつ加速して観察が可能である。

• Analyses of heterogeneous deformation and subsurface fatigue crack generation in alpha titanium alloy at low temperature

  Osamu Umezawa, Motoaki Morita, Takayuki Yuasa, Satoshi Morooka, Yoshinori Ono, Tetsumi Yuri, Toshio Ogata

  Advances in Cryogenic Engineering-Materials   60   34 - 41   2014.01  [Refereed]  [Invited]

  Introduction and explanation (scientific journal)   Joint Work

  　View Summary

  チタン合金の低温高サイクル疲労において{0001}ファセットを起点とする内部き裂発生について従来文献をレビューした。中性子回折実験と完全拘束モデルによる検討につてもまとめ、{0001}開口応力の存在を指摘した。

  DOI

• Ecomaterials in the global eco-society: present situation and future prospects

  O. Umezawa, K. Halada, K. Shinohara

  Materials Science Forum   555   1 - 7   2007

  Introduction and explanation (bulletin of university, research institution)   Joint Work

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Industrial Property 【 display / non-display 】

Industrial Property 【 display / non-display 】

• Ultra-fine texture steel and method for producing it

  Patent No 199752

  S. Torizuka, K. Tsuzaki, K. Nagai and O. Umezawa

• Ultra-fine grain steel and method for producing it

  Patent No 6221178

  S. Torizuka, K. Tsuzaki, K. Nagai and O. Umezawa

• Production method of ultra fine grain steel

  Industrial Property No 89103117  Patent No 153034

  S. Torizuka, O. Umezawa, K. Tsuzaki and K. Nagai

• Fine ferrite-based structure steel and production method thereof

  Industrial Property No 09/157,393  Patent No 6572716

  T. Hayashi, S. Torizuka, K. Tsuzaki, K. Nagai and O. Umezawa

• Ultra-fine texture steel and method for producing it

  Industrial Property No 98120620.4  Patent No ZL98120620.4

  S. Torizuka, K. Tsuzaki, K. Nagai and O. Umezawa

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Academic Awards Received 【 display / non-display 】

Academic Awards Received 【 display / non-display 】

• Best Structural Materials Paper

  2019.07.23   International Cryogenic Materials Conference  

  Winner： Norimitsu Koga, Weisi Zhang, Osamu Umezawa, Valentin Tschan, Jan Sas, Klaus-Peter Weiss

• Sawamura Thesis Prize, The Iron and Steel Institute of Japan

  2004.03    

• Tawara Thesis Prize, The Iron and Steel Institute of Japan

  2001.03    

• International Cryogenic Materials Conference, Best Structural Materials Paper 1991

  1993.07    

• Honda Research Promotive Prize, The Honda Memorial Foundation

  1993.05    

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Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• Grant-in-Aid for Scientific Research(C)

  Project Year： 2016.04  -  2019.03 

Presentations 【 display / non-display 】

Presentations 【 display / non-display 】

• A Subsurface fatigue crack generation model in near alpha titanium at low temperature

  Osamu Umezawa, Weibo Li

  Thermec 2018  ( Paris)  2018.07.12  

• Growth of ecomaterials and eco-efficiency in major metallic structural materials

  Osamu Umezawa, Yoshikazu Shinohara, Kohmei Halada

  13th International Conference on Ecomaterials 2017 (ICEM13)  (Bangkok, Thailand)  2017.11.20  

• Subsurface Crack Generation Under Rolling Contact Fatigue in Steels

  The First Symposium on Ecomaterials and Processing Technology  2012.10.22  

• Crack Growth Modeling Under Rolling Contact Fatigue

  2012.09  

• Activities in Solid State Materials and Engineering course, Yokohama National University

  4th International Symposium between Yokohama National University and Changwon National University  2012.08.25  

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Past of Collaboration and Commissioned Research 【 display / non-display 】

Past of Collaboration and Commissioned Research 【 display / non-display 】

• International Cooperative Research Project

  International Cooperative Research  

  Project Year： 1993  -  1995 

Social Contribution(Extension lecture) 【 display / non-display 】

Social Contribution(Extension lecture) 【 display / non-display 】

• "

  2019.03

  　

  　

• "

  2018.03

  　

  　

• 13th International Conference on Ecomaterials

  2017.11

  　

  　

• "

  2017.03

  　

  　

• 7th New Methods of Damage and Failure Analysis of Structural Parts

  2016.11

  　

  　

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