Quantitative analysis of Mo solute drag effect on ferrite and bainite transformations in Fe-0.4C-0.5Mo alloy
Quantitative analysis of Mo solute drag effect on ferrite and bainite transformations in Fe-0.4C-0.5Mo alloy
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DOI：
10.1016/j.actamat.2019.07.040
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发表时间：
2019-09-15
期刊：
影响因子：
9.4
通讯作者：
Furuhara, Tadashi
中科院分区：
文献类型：
--
作者：
Miyamoto, Goro;Yokoyama, Kentaro;Furuhara, Tadashi
钼的添加被广泛用于延缓钢的铁素体相变，提高钢的淬透性。众所周知，Mo在铁素体/奥氏体界面处的偏聚引起了溶质拖曳效应(SDE)，降低了铁素体/奥氏体界面上的迁移速度，而Mo对贝氏体相变的阻碍作用不明显。然而，元素偏析、溶质拖曳效应及其与界面性质的关系还没有得到定量的阐明。因此，本文定量地研究了Fe-0.4%C-0.5%Mo(质量%)合金中铁素体和贝氏体相变过程中Mo偏析的数量、界面迁移过程中的能量耗散以及界面取向关系。与非K-S OR界面处的Mo偏析比与近K-S OR界面处的Mo偏析更明显。Mo在非K-S界面的偏聚量随着相变时间的增加而增加，而能量耗散则减少。利用优化的偏析能和界面厚度，在非K-S界面测得的Mo偏析和能量耗散量与SDE模型吻合较好。另一方面，尽管Mo偏析很小，但贝氏体/奥氏体界面处的能量耗散很大，这与SDE模型不一致。(C)2019 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
Mo addition is widely used to retard ferrite transformation and increase hardenability of steels. It has been well recognized that Mo segregation at ferrite/austenite interface induces solute drag effect (SDE) and reduces migration rate of ferrite/austenite interface while retardation by Mo is less obvious in bainite transformation. However, element segregation, solute drag effects and its interface character dependence have not been clarified quantitatively. Therefore, in the present study, amount of Mo segregation, energy dissipation during interface migration and interface orientation relationship (OR) in ferrite and bainite transformations in Fe-0.4%C-0.5%Mo (mass%) alloy have been investigated quantitatively. Mo segregation at interfaces with non K-S OR is more significant than that at interface with near K-S OR. Amount of Mo segregation at interface with non K-S OR increases with increase in transformation time investigated while energy dissipation decreases. The amount of Mo segregation and energy dissipation measured at non K-S interface coincides well with SDE model using optimized segregation energy and interface thickness. On the other hand, energy dissipation at bainite/austenite interface is large in spite of negligibly small Mo segregation, which is inconsistent with the SDE model. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.