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Affiliation |
Faculty of Engineering, Division of Materials Science and Chemical Engineering |
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Date of Birth |
1970 |
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Research Fields, Keywords |
texture, Thermomechanical treatment, Solid solution alloy, High temperature deformation, Texture control |
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Mail Address |
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OKAYASU Kazuto
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ORCID
Degree 【 display / non-display 】
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Bachelor of Engineering - Toyota National College of Technology
Academic Society Affiliations 【 display / non-display 】
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2001.6
The Japan Institute of Metals
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2002
The Japan Institute of Light Metals
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2013.4
The Japan Society for Heat Treatment
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2018.12
The Japan Society of Mechanical Engineers
Research Areas 【 display / non-display 】
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Nanotechnology/Materials / Structural materials and functional materials
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Nanotechnology/Materials / Material processing and microstructure control
Papers 【 display / non-display 】
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Fukutomi Hiroshi, Okayasu Kazuto, Onuki Yusuke, Hasegawa Makoto, Kobayashi Equo, Strnadel Bohumir, … Show more authors
Fukutomi Hiroshi, Okayasu Kazuto, Onuki Yusuke, Hasegawa Makoto, Kobayashi Equo, Strnadel Bohumir, Umezawa Osamu Hide authors
MATERIALS TRANSACTIONS 63 ( 2 ) 148 - 156 2022.2 [Reviewed]
Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人 日本金属学会 Joint Work
<p>The relationship between the mechanism of high temperature deformation and the evolution behavior of microstructure and the texture during deformation, which has been found in various solid solution alloys, is clarified. It is shown that the preferential dynamic grain growth (PDGG) mechanism proposed by the authors can explain the behavior of microstructure change as well as texture change of all studied alloys without contradiction. The essential aspect of the PDGG mechanism is the preferential growth of crystal grains with the orientation stable for deformation and with low Taylor factor in the given deformation mode. It is concluded that the Taylor factor corresponds to dislocation density and stored energy during the high temperature deformation of solid solution alloys when viscous glide of dislocations is the rate controlling process. The possibility of the occurrence of the PDGG mechanism in materials other than solid solution alloys is also discussed.</p>
Other Link： https://cir.nii.ac.jp/crid/1390290846626516352
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Fukutomi Hiroshi, Suzuki Shigeru, Nakajima Itaru, Okayasu Kazuto, Hasegawa Makoto, Onuki Yusuke
Tetsu-to-Hagane 107 ( 4 ) 312 - 320 2021.4 [Reviewed]
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Iron and Steel Institute of Japan Joint Work
Other Link： https://ci.nii.ac.jp/naid/130008009135
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Fukutomi Hiroshi, Park Hyung-Gyun, Kim Kwon-Hoo, Okayasu Kazuto, Hasegawa Makoto, Umezawa Osamu
Journal of the Japan Institute of Metals and Materials 83 ( 8 ) 264 - 272 2019.8 [Reviewed]
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Institute of Metals and Materials Joint Work
<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<sup>−2</sup> s<sup>−1</sup>, 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>
Other Link： https://ci.nii.ac.jp/naid/130007683520
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Kwon Hoo Kim, Kazuto Okayasu, Hiroshi Fukutomi
Materials Science Forum 879 938 - 942 2017 [Reviewed]
Language：English Publishing type：Research paper (international conference proceedings) Publisher：Scientific.Net Joint Work
Other Link： https://www.scientific.net/MSF.879
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Hyung-Gyun Park, Kwon-Hoo Kim, Kazuto Okayasu, Makoto Hasegawa, Hiroshi Fukutomi
Journal of the Japan Institute of Metals and Materials 80 ( 10 ) 612 - 619 2016.10 [Reviewed]
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Institute of Metals and Materials Joint Work
Other Link： https://www.jstage.jst.go.jp/article/jinstmet/80/10/80_J2016011/_article/-char/en
Review Papers 【 display / non-display 】
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Introduction to Crystallographic Texture -Expression Methods and Formation Processes-
Hiroshi FUKUTOMI and Kazuto OAKAYASU
Journal of the Japan Society for Technology of Plasticity 54 ( 2 ) 91 - 95 2013.2
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (scientific journal) Joint Work
Other Link： https://www.jstage.jst.go.jp/article/sosei/54/625/54_91/_article/-char/en
Industrial Property Rights 【 display / non-display 】
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Metallic material as a solid solution having a body-centered cubic (bcc) structure, an orientation of crystal axis <001> of which is controlled, and method of manufacturing the same
Hiroshi Fukutomi, Kazuto OKayasu, Yusuke Onuki
Applicant：National University Corporation, Yokohama National University
Application no：2012-501909 Date applied：2011.2.28
Announcement no：WO2011/105609A1 Date announced：2011.9.1
Patent/Registration no：5492975 Date issued：2014.3.7
Country of applicant：Domestic
Awards 【 display / non-display 】
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71st The Japan Institute of Metals and Materials The Best Paper Award
2023.9 The Japan Institute of Metals and Materials Preferential Dynamic Grain Growth Mechanism Enabling the Control of Microstructure and Texture by High Temperature Deformation: Experimental Evidence and Applicability
Individual or group name of awards：Hiroshi Fukutomi, Kazuto Okayasu, Yusuke Onuki, Makoto Hasegawa, Equo Kobayashi, Bohumir Strnadel, Osamu Umezawa
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Kanto branch distinguished service awar
2022.3 The Japan Institute of Light Metals
Individual or group name of awards：Kazuto Okayasu
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AY2014 Best Paper Award of The Japan Society for Heat Treatment (scientific paper)
2013.6 The Japan Society for Heat Treatment Deformation Behavior and Texture Formation in AZ80 Magnesium Alloy during Uniaxial Compression Deformation at High Temperatures
Individual or group name of awards：Jinuk(Kwonhoo) KIM, Kazuto OKAYASU, Hiroshi FUKUTOMI
Grant-in-Aid for Scientific Research 【 display / non-display 】
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Fabrication of magnetic efficiency evaluation device for electromagnetic steel sheet with ideal crystal orientation
2016.4 - 2017.3
Grant-in-Aid for Scientific Research Grant-in-Aid for Encouragement of Scientists
Investigator(s)：Kazuto OKAYASU
Grant type：Competitive
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Basic research for improvement of bendability in aluminum alloy using single crystal sample
2010.4 - 2011.3
Grant-in-Aid for Scientific Research Grant-in-Aid for Encouragement of Scientists
Investigator(s)：Kazuto OKAYASU
Grant type：Competitive
Other external funds procured 【 display / non-display 】
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5th International Conference on Recrystallization & Grain Growth
2013.5
Local Government
Investigator(s)：Kazuto OKAYASU
Committee Memberships 【 display / non-display 】
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125th JILM Annual Meeting exective committee
2013.2 - 2013.11 exective committee
Committee type：Academic society
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123rd JILM Annual meeting executive committee
2012.2 - 2012.11 executive committee
Committee type：Academic society
Social Contribution(Extension lecture) 【 display / non-display 】
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平成24年度GMI講座「結晶配向評価講座ー座学と実習ー
Role(s)： Lecturer
グリーンマテリアルイノベーション研究拠点 横浜国立大学 2012.10
Audience： Researchers, Company
Type：Seminar, workshop
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集合組織の測定実習（EBSD, XRD）
Role(s)： Lecturer
日本塑性加工学会 東京・南関東支部若手の会第9回勉強会 横浜国立大学 2010.12
Audience： Researchers
Type：Seminar, workshop
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軽金属基礎技術講座「集合組織の測定法」
Role(s)： Lecturer
軽金属学会 横浜国立大学 2009.4
Audience： Researchers
Type：Seminar, workshop