ANISOTROPIC HARDENING IN SINGLE-CRYSTALS AND THE PLASTICITY OF POLYCRYSTALS

Based on the dislocation structures developed during plastic deformation, an anisotropic hardening law is developed to describe the latent hardening behavior of slip systems under multislip. This theory incorporates the concept of isotropic hardening, kinematic hardening, and the two-parameter representation; it automatically includes the strength differential between the forward and reversed slips and between the acute and obtuse cross slips. The self-hardening modulus of a slip system is found to be 'associated' with the latent hardening law involved, and, based on some experimental evidence, two specific sets of self-hardening modulus are suggested. Within the range of experimentally measured latent hardening ratio of slip systems, the anisotropic, theory is also used to calculate the motion of yield surface of a polycrystal.