Grain-scale experimental validation of crystal plasticity finite element simulations of tantalum oligocrystals
Grain-scale experimental validation of crystal plasticity finite element simulations of tantalum oligocrystals
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DOI：
10.1016/j.ijplas.2014.05.004
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发表时间：
2014-09-01
影响因子：
9.8
通讯作者：
Weinberger, C. R.
中科院分区：
文献类型：
--
作者：
Lim, H.;Carroll, J. D.;Weinberger, C. R.
在这项工作中，粗晶粒体心立方（BCC）钽的晶粒尺度弹塑性变形行为进行了模拟，使用晶体塑性有限元法（CP-FEM）和晶内应变和旋转场的实验测量进行比较。为了减轻未知的亚表面微观结构的影响，钽拉伸试样与毫米级晶粒提供了几乎恒定的微观结构，通过拉伸棒的厚度。通过三种方式进行实验验证：（1）电子背散射衍射（EBSD）来绘制晶内旋转，（2）高分辨率数字图像相关（HR-DIC）来绘制表面应变场，以及（3）表面轮廓术来绘制面外地形畸变。为了确保与实验的直接比较，在模型中仔细复制了初始微观结构和边界条件的细节。使用这种新的体心立方CP-FEM模型的钽的变形预测同意相当不错的实验测量。此外，该模型成功地预测了大塑性应变下试样的失效位置。探讨了影响体心立方CP-FEM预测的几个模型参数，如网格依赖性，体心立方金属中活动滑移面的选择和初始晶体取向的分配。(C)2014爱思唯尔有限公司版权所有。
In this work, the grain-scale elastoplastic deformation behavior of coarse-grained body centered cubic (BCC) tantalum was simulated using a crystal plasticity finite element method (CP-FEM) and compared to experimental measurements of intragranular strain and rotation fields. To mitigate the effects of unknown subsurface microstructure, tantalum tensile specimens with millimeter-sized grains provided nearly constant microstructure through the thickness of the tensile bar. Experimental validation was performed in three ways: (1) electron backscatter diffraction (EBSD) to map intragranular rotation, (2) high-resolution digital image correlation (HR-DIC) to map the surface strain field, and (3) surface profilometry to map the out-of-plane topographic distortion. To ensure a direct apples-to-apples comparison to experiments, the details of the initial microstructure and boundary conditions were carefully replicated in the model. The deformation predictions using this novel BCC CP-FEM model for tantalum agree reasonably well with the experimental measurements. In addition, the model successfully predicted the failure location of a specimen subjected to large plastic strains. Several model parameters were explored that influence the BCC CP-FEM predictions such as the mesh dependence, the choice of active slip planes in BCC metals and the assignment of initial crystal orientations. (C) 2014 Elsevier Ltd. All rights reserved.