2010 Fiscal Year Final Research Report
Evaluation of the boundary strength of ferrous martensite through a micromechanical test
Project/Area Number |
21760550
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Research Category |
Grant-in-Aid for Young Scientists (B)
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Allocation Type | Single-year Grants |
Research Field |
Structural/Functional materials
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Research Institution | Kyoto University (2010) Tokyo Institute of Technology (2009) |
Principal Investigator |
SHIBATA Akinobu Kyoto University, 工学研究科, 助教 (60451994)
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Project Period (FY) |
2009 – 2010
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Keywords | マルテンサイト / 鉄合金 / 粒界強度 / マイクロサイズ機械試験 / 機械的特性 |
Research Abstract |
We investigated the block boundary and sub-block boundary strengths of martensite evaluated through a micromechanical test. The sub-block boundaries contribute very little to the macroscopic strength of martensite. In contrast, the existence of a block boundary in the specimen greatly increased the strength. In addition, the block boundary induced a serrated flow and load drop in the load-displacement curve. The load drop and serrated flow were attributed to dislocation pile-up and subsequent propagation of dislocations across the block boundary. In a microstructural observation of specimens after deformation, we found that a block boundary significantly restricts the motion of dislocations, while sub-block boundary does not. We concluded that the block boundary is the most effective grain boundary for strength in martensite.
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