多晶铍微观弹性失配行为的数值分析

发布时间：2018-10-16 16:56

【摘要】：考虑了晶粒取向随机的影响,分别建立了多晶铍的规则和非规则晶形二维多晶模型,对多晶铍的微观弹性失配行为进行了有限元(FEM)数值分析。规则模型晶粒形状取为正方形或正六边形;非规则模型利用Voronoi方法获得接近真实的非规则形状晶粒。考虑到单晶体力学性能的各向异性,对具有HCP结构单晶铍晶粒的含有5个参数的弹性刚度矩阵进行坐标变换,得到任意取向铍晶粒的弹性性能参数。将各组弹性性能参数随机地赋给各个晶粒,实现在晶粒取向随机化分布条件下对弹性性能差异性考虑的目的。基于以上工作对两类铍多晶模型进行了FEM应力分析,结果表明,两类不同模型的失配应力集中均发生在晶界处;相比规则多晶模型,不规则多晶模型的弹性失配效应更为显著;最大失配应力较平均应力(即不考虑弹性失配影响时的应力)高出10%左右。
[Abstract]:Considering the random effect of grain orientation, the regular and irregular two-dimensional polycrystalline models of polycrystalline beryllium were established, and the micro-elastic mismatch behavior of polycrystalline beryllium was numerically analyzed by finite element (FEM). The regular model grain shape is taken as square or hexagonal, and the irregular model is used to obtain the real irregular shape grain by using Voronoi method. Considering the anisotropy of single crystal mechanical properties, the elastic stiffness matrix with five parameters for single crystal beryllium crystal with HCP structure was transformed in coordinate, and the elastic property parameters of beryllium grain with arbitrary orientation were obtained. Each group of elastic properties parameters are randomly assigned to each grain to realize the purpose of considering the difference of elastic properties under the condition of random distribution of grain orientation. Based on the above work, the FEM stress analysis of two kinds of beryllium polycrystalline models is carried out. The results show that the mismatch stress concentration of the two kinds of models occurs at grain boundary, and the elastic mismatch effect of irregular polycrystalline model is more obvious than that of regular polycrystalline model. The maximum mismatch stress is about 10% higher than the average stress (that is, the stress without the effect of elastic mismatch).
【作者单位】：宁夏大学宁夏光伏材料重点实验室;西北稀有金属材料研究院特种材料重点实验室暨稀有金属铍材行业重点实验室;
【基金】：国家自然科学基金项目(11062010,51474177) 宁夏自然科学基金项目(NZ14038)资助
【分类号】：TG146.24

【参考文献】