Understanding martensite and twin formation in austenitic steels: A model describing TRIP and TWIP effects
Understanding martensite and twin formation in austenitic steels: A model describing TRIP and TWIP effects
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DOI：
10.1016/j.actamat.2017.02.004
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发表时间：
2017-04-15
期刊：
影响因子：
9.4
通讯作者：
Rivera-Diaz-del-Castillo, P. E. J.
中科院分区：
文献类型：
--
作者：
Galindo-Nava, E. I.;Rivera-Diaz-del-Castillo, P. E. J.
本文对奥氏体钢中α-马氏体、α ′-马氏体和孪晶的演变作了统一的描述。通过考虑分级排列的纳米级孪晶和孪晶（胚胎）的演化，获得了微米级孪晶和孪晶带的形成。当这些结构形成时的临界尺寸和施加的应力通过使它们的形成自由能最小化来获得。形成e板或孪晶的区别在于它们结构中重叠堆垛层错的数量。提出了一个基于临界胚体尺寸、分辨剪切应力和胚体数密度的成核速率判据。基于Olson和Cohen的经典α '-马氏体转变模型，认为α'的形核率与ε的形核率成正比。这些结果，结合位错为基础的近似，规定的微观结构和流动应力响应的钢中的相变诱导塑性（TRIP）和/或孪生诱导塑性（TSTK）的影响操作，这些包括奥氏体不锈钢和高Mn钢。定义了不同应变水平下层错能对孪晶、α ′和孪晶作用范围的影响图。还探讨了化学成分对不锈钢显微组织和力学响应的影响。这些结果允许识别潜在的组成方案时，TRIP和/或TTRIP效应在奥氏体钢中得到促进。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
A unified description for the evolution of epsilon- and alpha'-martensite, and twinning in austenitic steels is presented. The formation of micron-scale epsilon and twin bands is obtained by considering the evolution of hierarchically arranged nano-sized epsilon and twins (embryos). The critical size and applied stress when these structures form is obtained by minimising their free energy of formation. The difference between forming an e plate or a twin lies in the number of overlapping stacking faults in their structure. A nucleation rate criterion is proposed in terms of the critical embryo size, resolved shear stress and embryo number density. Based on Olson and Cohen's classical alpha'-martensite transformation model, the nucleation rate of alpha' is considered proportional to that for epsilon. These results, combined with dislocation-based approximations, are employed to prescribe the microstructure and flow stress response in steels where transformation-induced-plasticity (TRIP) and/or twinning-induced-plasticity (TWIP) effects operate; these include austenitic stainless and high-Mn steels. Maps showing the operation range of epsilon, alpha' and twinning in terms of the stacking fault energy at different strain levels are defined. Effects of chemical composition in the microstructure and mechanical response in stainless steels are also explored. These results allow identifying potential compositional scenarios when the TRIP and/or TWIP effects are promoted in austenitic steels. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.