FCC晶体中孔洞的聚合行为研究

Research on Void Coalescence Behavior in FCC Single Crystal

通过编写率相关用户子程序UMAT,实现了有限元计算中晶体塑性本构关系描述。采用含两个球形孔洞单晶模型,模拟分析了FCC晶体中不同晶体取向下孔洞的聚合行为。计算结果表明孔洞的聚合与晶体取向密切相关,在变形过程中,随着晶体取向不同,孔洞形状、长大方向和孔洞间韧带宽度也不同,就Cube、Goss、Copper和Brass四种初始取向而言,Cube取向中的孔洞的聚合效应最强烈最易聚合。单晶体中两孔洞间韧带区变形充分且孔洞沿韧带方向显著生长会加快孔洞的聚合速度。

A rate-dependent user subroutine UMAT was written in Fortran language, which could be used for describing the crystal plasticity constitutive relation in the finite element calculation. A single crystal model including two 3D spherical voids was established to study the aggregation behavior of voids with different crystal orientations in FCC crystal. The computed results of different crystallographic orientations were compared, which shows that significant shape, growth direction and ligament are different with different crystal orientations in the modification process. The coalescence effect of cube orientation voids is found to be the strongest and easiest to polymerization by comparing the four initial crystallographic orientations （cube orientation, goss orientation, copper orientation, brass orientation）. And the main growth direction of two voids in single crystal is consistent with the ligament direction, and the easier deformation ligament zone will accelerate the rate of coalescence of voids.