Crystal Plasticity Analysis on Redistributions of Strains and Activity Changes of Slip Systems in α-Ti under Cyclic Loading

Abstract

We conducted crystal plasticity analysis of a bicrystal model using a crystal plasticity finite element method (CPFEM), and the activities of slips systems in the α-phase of Ti-6Al-4V alloys (Ti-64) under cyclic loading were investigated. The crystal orientations were set such that prismatic <a> and basal slip systems were the primary slip systems in the crystal grains, respectively. The results showed that the occurrence of work hardening in a crystal grain decreased the volume of deformation and increased those of elasto-plastic deformations in neighboring crystal grains. The phenomenon leads to activation of slip systems in neighboring crystal grains. Thus, although the prismatic <a> slips initially operates under a cyclic loading, the basal slip system in the neighboring crystal grains displays a potential for activation by work hardening on the prismatic <a> slip system. The mechanism of changes in activities of slip systems by the interaction between crystal grains can be explained by the wedge disclination-type deformation field.