2013 Fiscal Year Final Research Report
Dynamics of phase transformations in steel obtained by controlled heating
| Project/Area Number |
23360316
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Goro 東北大学, 金属材料研究所, 准教授 (60451621)
KAMIKAWA Naoya 東北大学, 金属材料研究所, 助教 (30530894)
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| Project Period (FY) |
2011-11-18 – 2014-03-31
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| Keywords | 逆変態 / 結晶学 / 相平衡 / 核生成・成長 / マルテンサイト / 拡散変態 |
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| Research Abstract |
In this study, microstructure change during reversion of steels was examined focussing on (1) effects of initial structure, (2) non-equilibrium partitioning of alloying elements, and (3) crystallographic constraints during reversion. Main results obtained are as follows.
In Fe-high Ni alloys, displacive transformation occurs during reversion with austenite memory. However, a high dislocation density in reversely transformed austenite induces recrystallization which results in disappearance of the memory effect during further holding. In Fe-Mn-C alloys, reversely transformed austenite exhibits two kinds of distinctive morphologies, granular and acicular. Those morphologies are different in crystallographic character with respect to martensite matrix. Also, it was revealed that the granular austenite is formed in non-equilibrium in the beginning and reaches to the equilibrium in the later stage of reversion.
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