2022 Fiscal Year Research-status Report
Investigation on the polymer-like deformation behavior in ultra-fine grained metastable austenitic steel
| Project/Area Number |
22K14509
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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, 講師 (00782038)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | deformation behavior / ultrafine grain / steel / martensitic |
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| Outline of Annual Research Achievements |
Research activities and research achievements in the academic year 2022 are as follows:
(1)Tensile deformation with in-situ neutron diffraction experiments were performed on the UFG 304 stainless steel at BL19-TAKUMI, JPARC, Japan. The transformation rate of deformation induced martensite and the phase stress partitioning between austenite matrix and martensite during the propagation of the huge Luders band were quantitatively evaluated by the neutron diffraction technique.
(2)Above results were summarized into a short paper submitted to the journal Scripta Materialia and now it is under review.
(3)An oral presentation was given in the international conference “The 7th International Conference on Advanced Steels (ICAS)” held on May 29 - June 1, 2022 Tsukuba, Japan.
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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 research is progressing more smoothly even than initially planned. That is because the literature survey, the preparation of the material and the experiments have been successfully performed without frustrations. In addition, the newly developed experimental equipment in BL19-TAKUMI, JPARC enabled a hybrid in-situ neutron diffraction and digital image correlation technique measurements on the deformation of the UFG stainless steel, which greatly accelerated the progressing of the research.
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| Strategy for Future Research Activity |
It has been revealed by the research results so far that the deformation induced martensitic transformation played a key role in the polymer-like deformation behavior of the UFG 304 stainless steel. Nevertheless, it is still unclear how different transformation rate of deformation induced martensitic transformation and different stress partitioning behaviors between austenite and martensite impact the huge Luders deformation (polymer-like deformation behavior) of the material. To this end, it is planned to systematically study the temperature dependence of the deformation behaviors of the UFG 304 stainless steel using in-situ neutron diffraction combined with digital image correlation in the forthcoming academic year 2023.
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| Causes of Carryover |
It was initially planned to order an alloy material (Fe-Ni-C alloy) from a company for the current research subject. However, procedures for ordering that material from the company and the fabrication of the material unexpectedly take 5~6 months, and it was impossible to place the order within the fisical year 2022. Therefore, ordering that alloy material was re-scheduled to the next fisical year (2023).
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