Grain refinement of structural metallic materials by accumulation of transformation strain

2014 Fiscal Year Final Research Report

• Project/Area Number: 25630315
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Material processing/Microstructural control engineering
• Research Institution: Tohoku University
• Principal Investigator: MIYAMOTO Goro 東北大学, 金属材料研究所, 准教授 (60451621)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: マルテンサイト変態 / 逆変態 / 組織微細化 / 結晶学

Outline of Final Research Achievements

In order to establish novel grain refinement method, we've investigated microstructure change during cyclic displacive forward and reverse transformations. It was found that displacive reversion takes place in Fe-18Ni and Fe-23Ni alloys. As a results of reversion and forward transformations in Fe-Ni alloy, grain size decreases although further refinement cannot be achieved with increasing the number of cycles. On the other hand, grain size decreases continuously with increasing number of cycles in carbon added alloy. Eventually, sub-micron grain can be obtained after 10 cycles in this alloy.

Free Research Field

金属組織制御学