Study of SPF technique applied trasformation super plasicty on ferritic steel

Research Project

Project/Area Number	18K03585
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 14020:Nuclear fusion-related
Research Institution	National Institute for Fusion Science
Principal Investigator	Noto Hiroyuki 核融合科学研究所, ヘリカル研究部, 助教 (50733739)
Project Period (FY)	2018-04-01 – 2023-03-31
Project Status	Completed (Fiscal Year 2022)
Budget Amount *help	¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000) Fiscal Year 2022: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2021: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Keywords	変態超塑性 / 低放射化フェライト鋼 / 金属加工 / 超塑性成形
Outline of Final Research Achievements	Reduced activation ferritic-martensitic (RAFM) steels have a critical issue of poor workability　(low elongation and high yield strength). As an innovative means of processing RAFM, we have focused on “Transformation Super plasticity (SP)”　in this study. In this theme, the effect of thermal cyclic heat treatments on the complex deformation by isostatic press was researched, implying the importance of “rate of thermal cycles”. In addition, the microstructural observations in view of “the strengthening particles” was also before and after Transformation Super plasticity. These results would contribute to the advanced metallurgical technology in target of transformation materials and the advanced metallography in mean of precipitation strengthening in the future.
Academic Significance and Societal Importance of the Research Achievements	本研究課題では、超塑性成形を専門とする企業と連携し研究を行うことにより、かなり簡易な手法によりＳＰＦ技術と熱サイクルを組み合わせた試験（複合変形のための内圧試験体の作成と試験方法）が可能であることが示された。このような成果により、本課題終了後に更なる発展が期待され、産学連携といった社会的意義を持つと考えている。また、変態超塑性後の組織を観察することにより、強化粒子の変化も観察された。このような結果は材料学的にも大きな意義を持つと考えている。