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

摘要

Four crystal plasticity codes, the viscoplastic Material Point Simulator (MPS) developedat Cornell and the ViscoPlastic Self-Consistent code (VPSC7b) developed at LANL, and twoelastic-viscoplastic codes developed at Drexel University, were employed to calculatedeformation textures and mechanical properties of model polycrystalline specimens bysimulating isochoric, free upsetting. Uniaxial compression of a model sample with a startingrandom texture of 5000 grains was carried out at a constant true strain rate of 0.001/s to a truestrain 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, unalloyedTi. Both non-hardening and linear hardening conditions were investigated. Different strain-ratesensitivities simulated deformation conditions appropriate to ambient and elevated temperatureconditions. All codes permitted use of the Taylor homogenization hypothesis, resulting in anupper bound for the mechanical properties. All codes produce essentially identical results for thesame input material, homogenization hypothesis and deformation conditions. For comparison,one alternative homogenization hypothesis to model grain interactions was examined for each ofthe MPS and VPSC7b codes.