FCC晶体中不均匀变形对空洞长大的影响

通过编制率相关有限元用户子程序,采用一个单胞模型研究了FCC晶体中孔洞在单晶及晶界的长大行为,分析了由于晶体取向及变形失配对孔洞长大和聚合的影响。研究结果表明：孔洞的形状和长大方向与晶体取向密切相关;晶界上孔洞的长大速度大于单晶中孔洞的长大速度;晶粒间的变形失配加速了晶界上孔洞的长大趋势,因而使材料易发生沿晶断裂,随着晶粒间取向因子差异的增加,孔洞越易沿着晶界长大。

The effects of heterogeneous deformation on void growth in FCC crystals

To investigate the influence of crystallographic orientation and deformation mismatch on the growth and coalescence of spherical void, a unit cell was used to address the growth behavior of voids in single crystals and voids located at grain boundary in FCC crystals with the three dimensional crystal plasticity finite element method, which was implemented with the rate dependent crystal plasticity theory as user material subroutine. Simulation results show that the void shape and growth direction significantly depend on the crystallographic orientation, and the growth rate of voids at the grain boundary of the two-grain is faster than that in single crystal. Due to inter-grain heterogeneous deformation, the growth of void located at the grain boundary accelerated, and the material trends to fail by intergranular fracture. With the orientation factor’s difference between the two grains increasing, the void prefers to coalescence along grain boundary.