Numerical study of the stress state of a deformation twin in magnesium
Numerical study of the stress state of a deformation twin in magnesium
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DOI：
10.1016/j.actamat.2014.10.048
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发表时间：
2015-02-01
期刊：
影响因子：
9.4
通讯作者：
Tome, C. N.
中科院分区：
文献类型：
--
作者：
Kumar, M. Arul;Kanjarla, A. K.;Tome, C. N.
由于孪生相变剪切的调节，我们数值研究了形变孪生的局域应力状态在孪生区域内及其邻近区域的分布。对基于快速傅立叶变换的全场弹粘塑性公式进行了修正，考虑了变形孪生引起的剪切变形应变。我们进行了两种类型的孪生相变模拟：(I)完全嵌入单晶内的孪晶和(Ii)终止于晶界的孪晶前沿。结果表明：(A)所产生的应力分布更多地取决于剪切转变，而不是孪晶的晶内特征或相邻晶粒的取向；(B)孪晶平面上沿孪晶方向的剪切应力沿孪晶母体界面是不均匀的；以及(C)孪晶和含有孪晶的母晶中的剪应力平均值有很大差异。我们讨论了这些局部应力对孪晶的传播和生长的影响，以及我们的发现对形变孪生的建模的意义。爱思唯尔有限公司代表Acta Materialia Inc.出版。
We present here a numerical study of the distribution of the local stress state associated with deformation twinning in Mg, both inside the twinned domain and in its immediate neighborhood, due to the accommodation of the twinning transformation shear. A full-field elastoviscoplastic formulation based on fast Fourier transformation is modified to include the shear transformation strain associated with deformation twinning. We have performed two types of twinning transformation simulations with: (i) the twin completely embedded inside a single crystal and (ii) the twin front terminating at a grain boundary. We show that: (a) the resulting stress distribution is more strongly determined by the shear transformation than by the intragranular character of the twin or the orientation of the neighboring grain; (b) the resolved shear stress on the twin plane along the twin direction is inhomogeneous along the twin parent interface; and (c) there are substantial differences in the average values of the shear stress in the twin and in the parent grain that contains the twin. We discuss the effect of these local stresses on twin propagation and growth, and the implications of our findings for the modeling of deformation twinning. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.