A COMPARISON OF DEFORMATION TEXTURES AND MECHANICAL PROPERTIES PREDICTED BY DIFFERENT CRYSTAL PLASTICITY CODES

摘要

Four crystal plasticity codes, the viscoplastic Material Point Simulator (MPS) developed at Cornell and the ViscoPlastic Self-Consistent code (VPSC7b) developed at LANL, and two elastic-viscoplastic codes developed at Drexel University, were employed to calculate deformation textures and mechanical properties of model polycrystalline specimens by simulating isochoric, free upsetting. Uniaxial compression of a model sample with a starting random texture of 5000 grains was carried out at a constant true strain rate of 0.001/s to a true strain of 1.0 with 0.02 strain increments. Material properties simulated a face-centered cubic (FCC) alloy, Type 304 Stainless Steel, and a hexagonal close-packed (HCP) material, unalloyed Ti. Both non-hardening and linear hardening conditions were investigated. Different strain-rate sensitivities simulated deformation conditions appropriate to ambient and elevated temperature conditions. All codes permitted use of the Taylor homogenization hypothesis, resulting in an upper bound for the mechanical properties. All codes produce essentially identical results for the same input material, homogenization hypothesis and deformation conditions. For comparison, one alternative homogenization hypothesis to model grain interactions was examined for each of the MPS and VPSC7b codes.