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。
With taking random distributions of grain orientation into account,2D models of polycrystalline beryllium with regular or irregular grain shapes were established,respectively,for simulating micro elastic mismatch behaviors of polycrystalline beryllium using finite element method（ FEM） analysis. Grains in the regular model were set as square or hexagonal shapes. With Voronoi diagram method,grains with irregular shape close to real situation were obtained in the irregular model. Considering the anisotropic mechanical properties of single crystal,the coordinate transformation of elastic stiffness matrix containing 5 independent parameters of monocrystal beryllium grain with HCP structure was carried out,and the elastic property parameters of grains of any orientation were obtained. Assigning these calculated parameters to different grains randomly,the aim of considering elastic property differences under the condition of random distributions of grain orientation was achieved. Based on the above work,the stress analysis on regular and irregular beryllium polycrystalline models was done by FEM. Calculation results showed that,for all models the elastic mismatch stress concentration always appeared on the grain boundaries,the elastic mismatch effect of the irregular model was more remarkable than that of regular models,and the maximal mismatch stress was about 10% higher than the mean stress（ the stress without considering elastic mismatch effects）.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第8期764-768,共5页
Chinese Journal of Rare Metals
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
关键词
多晶铍
VORONOI图
晶粒取向
弹性失配
有限元法(FEM)
polycrystalline beryllium
Voronoi diagram
grain orientation
elastic mismatch
finite element method（FEM）
