Microstructural evolution and cyclic softening / hardening response of a TRIP-assisted duplex stainless steel
Microstructural evolution and cyclic softening / hardening response of a TRIP-assisted duplex stainless steel
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TRIP 辅助双相不锈钢的微观结构演变和循环软化/硬化响应
DOI：
10.1016/j.msea.2021.141026
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Miao Jin
中科院分区：
文献类型：
--
作者：
Shuo Hao;Lei Chen;Zongyuan Zou;Peng Cheng;Qixiang Jia;Hongzhong Wang;Miao Jin
本文研究了TRIP强化双相不锈钢（DSS）在0.2 ~ 1.2%应变幅范围内的循环软化/硬化特性，并通过透射电镜观察了位错结构的演变，阐明了两相循环变形机制。在不同的应变幅（ea），测试DSS表现出不同程度的循环软化后，除了的情况下，初始循环硬化的ea= 0.2%，直接循环饱和。循环软化率（δ）对EA敏感，当EA>0.25%（EA>0.5%）时，δ持续下降。在近似循环至失效的试样中，随着ea的增加，铁素体中的位错结构主要以片、壁和/或不良胞的顺序发展，这对应于位错重排的逐渐增强，而γ→层错（SFs）→e→α′的应变诱发马氏体相变（SIMT）随着ea的增加而激活。认为这是δ值下降的主要原因。此外，通过分析循环滞回曲线二阶导数曲线上的“特征峰”与两相子结构演化的关系，进一步讨论了各相的循环响应。
Abstract In this work, the cyclic softening/hardening characteristics of a TRIP-assisted duplex stainless steel (DSS) was studied within the strain amplitude range of 0.2 ~ 1.2 % , and the evolution of dislocation structures was characterized by TEM to clarify the cyclic deformation mechanism of both phases. At various strain amplitudes (ea), the test DSS showed different levels of cyclic softening after an initial cyclic hardening except for the case of ea=0.2%, where a direct cyclic saturation was present. Cyclic softening rate ( δ ) was sensitive to ea, and particularly, it showed a continuous decrease at eap>0.25% (ea>0.5%). In the samples approximately cycled to failure, the dislocation structure in ferrite mainly developed in the order of patch, wall and/or poor-formed cell with the increasing ea, which corresponded to the progressively enhanced rearrangement of dislocation, while the strain-induced martensitic transformation (SIMT) with a sequence of γ→stacking faults (SFs)→e→α′ was activated with increasing ea, and it was considered to be a main cause for the decreasing δ . Moreover, the cyclic response of the individual phases was further discussed by analyzing the “characteristic peak” on the second derivative curve of cyclic hysteresis loop in relation to the evolution of substructures in the two phases.