Realistic microstructure-based modelling of cyclic deformation and crack growth using crystal plasticity
Realistic microstructure-based modelling of cyclic deformation and crack growth using crystal plasticity
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DOI：
10.1016/j.commatsci.2015.09.054
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发表时间：
2016
影响因子：
3.3
通讯作者：
F. Farukh;Liguo Zhao;R. Jiang;P. Reed;D. Proprentner;B. Shollock
中科院分区：
文献类型：
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作者：
F. Farukh;Liguo Zhao;R. Jiang;P. Reed;D. Proprentner;B. Shollock
采用晶体塑性理论，对一种低固溶线高温镍基高温合金的高温循环变形进行了有限元模拟。使用代表性体积元素（RVE）进行分析，该体积元素由从材料的SEM图像获得的真实微观结构组成。使用725 °C下的单调、应力松弛和循环试验数据来确定拟合过程的模型参数及其对RVE尺寸和随机晶粒取向的敏感性。结合扩展有限元法（XFEM），进一步应用晶体塑性模型预测表面裂纹扩展，并以累积塑性应变作为断裂准则。再次，现实的微观结构，从一个平面疲劳试样的表面上的裂纹位点，被用来创建裂纹扩展分析的有限元模型。预测进行了伪三维几何模型，类似于平面应力条件下在试样表面。裂纹部位的载荷水平由疲劳试样的粘塑性有限元分析确定。该模型能够预测不同取向晶粒生长速率的变化。
Using crystal plasticity, finite element analyses were carried out to model cyclic deformation for a low solvus high refractory (LSHR) nickel superalloy at elevated temperature. The analyses were implemented using a representative volume element (RVE), consisting of realistic microstructure obtained from SEM images of the material. Monotonic, stress-relaxation and cyclic test data at 725 °C were used to determine the model parameters from a fitting process and their sensitivity to RVE size and random grain orientation. In combination with extended finite element method (XFEM), the crystal plasticity model was further applied to predict surface crack growth, for which accumulated plastic strain was used as a fracture criterion. Again, realistic microstructure, taken from the cracking site on the surface of a plain fatigue specimen, was used to create the finite element model for crack growth analyses. The prediction was conducted for a pseudo-3D geometrical model, resembling the plane stress condition at specimen surface. The loading level at the cracking site was determined from a viscoplasticity finite element analysis of the fatigue specimen. The proposed model is capable of predicting the variation in growth rate in grains with different orientations.