Modeling the effect of neighboring grains on twin growth in HCP polycrystals
Modeling the effect of neighboring grains on twin growth in HCP polycrystals
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DOI：
10.1088/1361-651x/aa7bbb
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发表时间：
2017-09-01
影响因子：
1.8
通讯作者：
Tome, C. N.
中科院分区：
文献类型：
--
作者：
Kumar, M. Arul;Beyerlein, I. J.;Tome, C. N.
本文研究了六方密排晶体中形变孪晶周围局部应力状态与相邻晶粒取向的关系及其对孪晶抗增厚性的影响。我们使用一个最近开发的，全场弹粘塑性配方的基础上快速傅立叶变换，占孪生剪切变形所施加的孪生薄板。该研究适用于镁，锆和钛，因为这些HCP金属往往通过激活不同类型的滑移模式变形。分析表明，孪晶界上的局部应力沿着分布受相邻晶粒中最易变形模式相对于母晶中孪晶层的相对取向的强烈控制。一个几何表达式，捕捉这种父母邻居的关系，提出并纳入一个更大的规模，平均场粘塑性自洽模型来模拟孪晶增厚相邻晶粒取向的作用。我们表明，该方法提高了预测的孪晶面积分数分布与实验观察相比。
In this paper, we study the dependence of neighboring grain orientation on the local stress state around a deformation twin in a hexagonal close packed (HCP) crystal and its effects on the resistance against twin thickening. We use a recently developed, full-field elasto-visco-plastic formulation based on fast Fourier transforms that account for the twinning shear transformation imposed by the twin lamella. The study is applied to Mg, Zr and Ti, since these HCP metals tend to deform by activation of different types of slip modes. The analysis shows that the local stress along the twin boundary are strongly controlled by the relative orientation of the easiest deformation modes in the neighboring grain with respect to the twin lamella in the parent grain. A geometric expression that captures this parent-neighbor relationship is proposed and incorporated into a larger scale, mean-field visco-plastic self-consistent model to simulate the role of neighboring grain orientation on twin thickening. We demonstrate that the approach improves the prediction of twin area fraction distribution when compared with experimental observations.