EBSD analysis of dual γ/ε phase microstructures in tensile-deformed Fe-Mn-Si shape memory alloy
EBSD analysis of dual γ/ε phase microstructures in tensile-deformed Fe-Mn-Si shape memory alloy
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DOI：
10.1016/j.jallcom.2019.04.307
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发表时间：
2019-08-15
影响因子：
6.2
通讯作者：
Tsuchiya, Koichi
中科院分区：
文献类型：
--
作者：
Tasaki, Wataru;Sawaguchi, Takahiro;Tsuchiya, Koichi
用电子背散射衍射仪分析了Fe-28Mn-6Si-5Cr(质量分数)形状记忆合金在拉伸变形过程中形成的双伽马/epsilon相的结晶学和显微组织特征。分析是在拉伸变形到10%的应变和断裂的试件上进行的，分别在大约ms(25摄氏度)和略低于M-d(150摄氏度)。结果表明，变形温度对形变诱导相和残余伽马相的进一步塑性变形有影响。β相不同取向间的取向差夹角/轴分别为70.5°/<；110>；(Epsilon)和86°/<；110>；(Epsilon)，这可以用Shoji-Nishiyama关系和孪生关系来解释。随着变形温度和拉伸应变的升高，由于伽马相和e相位错活动明显，取向不良角偏离了结晶学关系。相稳定性的差异也导致了不同的相交组织：25℃的Epsilon孪晶，150℃的epsilon孪晶和90度旋转的g-奥氏体。这些结构有一个平行于<；101>；Gamma相交轴的共同旋转轴<；1120。在md以下，强塑性平衡的EPSILON-TRIP效应归因于位错密度的逐渐增加、应力集中的减少以及e相附近的调节机制。(C)2019爱思唯尔B.V.保留所有权利。
Crystallographic and microstructural features of a dual gamma/epsilon phase developed in an Fe-28Mn-6Si-5Cr (mass %) shape memory alloy under tensile deformation were analyzed by electron back-scattered diffraction. The analyses were carried out on specimens tensile-deformed to a 10% strain and to fracture, at around Ms (25 degrees C) and at just below M-d (150 degrees C), respectively. It suggests that the deformation temperature affects further plastic deformation in the deformation-induced epsilon-phase and the residual gamma-phase. The angle/axis of misorientation between different orientations of epsilon-phase were 70.5 degrees /< 110 >(epsilon) and 86 degrees / < 110 >(epsilon), which can be explained by the Shoji-Nishiyama relationship and twinning relationship in the gamma- and epsilon-phases. The misorientation angles deviated from the crystallographic relations when deformation temperature and tensile strain were increased, due to significant dislocation activity in the gamma- and e-phases. The phase stability difference also caused different variant intersection structures: epsilon-twins at 25 degrees C, the epsilon-twins and 90 degrees-rotated g-austenite at 150 degrees C. The structures have a common rotational axis of < 1120 >(epsilon) that is parallel to the intersection axis of < 101 >gamma. epsilon-TRIP effect on strengtheductility balance at just below Md was ascribed to a gradual dislocation density increase, less stress concentration and the accommodation mechanisms in the vicinity of e-phase. (C) 2019 Elsevier B.V. All rights reserved.