| Project/Area Number |
22K14509
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 26050:Material processing and microstructure control-related
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| Research Institution | Kyoto University |
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Principal Investigator |
高 斯 京都大学, 工学研究科, 准教授 (00782038)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2024: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2023: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2022: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | deformation behavior / ultrafine grain / steel / martensite / martensitic |
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| Outline of Research at the Start |
When the grain size of a commercial 304 type stainless steel is reduced to less than 1 or 2 micronmeter, it exhibits a stable necking that can propagate through the gauge portion of the sample during tensile deformation. It is a unique deformation behavior that has never been observed in metallic materials while often observed in polymer materials. This research aims at investigating the mechanism of such interesting “Polymer-like” deformation localization behavior in high strength ultra-fine grained (UFG) austenitic stainless steels.
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| Outline of Annual Research Achievements |
Research activities and achievements in academic year 2023 are as follows:
(1)Publication in Scripta Materialia: The research results on characterizing the polymer-like deformation behavior of the 304 stainless steel were published, which clarified the transformation speed and internal stress of the deformation induced martensite during the huge Luders band deformation of the ultra-fine grained 304 stainless steel.
(2)Keynote talk at JIM 2024 Spring Meeting: This talk introduced stress analysis methods using diffraction techniques for better understanding the deformation behavior associated with the transformation induced plasticity phenomenon in austenitic steels.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The originally planned experiments of tensile deformationat at different temperatures with in-situ irradiation and in-situ digital image correlation (DIC) measurements on the ultra-fine grained (UFG) 304 type stainless steel were successfully performed through collaborating with BL19-TAKUMI in Japan Proton Accelerator Research Complex (J-PARC). The temperature effect on the fraction and internal stress of the deformation-induced martensite phase during the Lueders deformation were successfully measured, which helped with quantitative interpretation on the "Polymer-like" deformation of the material.
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| Strategy for Future Research Activity |
In the next step, the experiment data of tensile deformation with neutron diffraction measurement performed at different temperatures on the ultra-fine grained 304 stainless steel will be analyzed for establishing the constitutive equations describing the effect of deformation induced martensitic transformation on the stress-strain relation.
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