Developing anisotropic yield models of polycrystalline tantalum using crystal plasticity finite element simulations

In this work, plastic anisotropy of polycrystalline tantalum is characterized by meso-scale crystal plasticity-finite element (CP-FE) simulations. Initial texture and grain morphology determined from electron backscatter diffraction (EBSD) measurements were incorporated into a three dimensional polycrystalline microstructure generated by grain growth simulations using kinetic Monte Carlo (kMC) Potts model. CP-FE simulations using such a polycrystalline representative volume element accurately capture anisotropic mechanical behaviors of polycrystalline tantalum. Furthermore, the CP-FE simulations are used to parameterize the classic Hill's anisotropic yield function, which is then employed in dynamic finite element simulations of Taylor impact tests. The predicted impacted cylinder shape agrees well with experimental observation, particularly in regard to anisotropic behavior. This work demonstrates a direct link between grain scale microstructural features and anisotropic mechanical behaviors of polycrystalline metals.