A MODEL OF MICROSTRUCTURE EVOLUTIONUNDER HIGH- STRAIN RATE DEFORMATION OF COPPER

A physical model of high-strain rate deformation metallic materials has been developed to describe the evolution microstructure during process. The is based on representations mechanisms grain boundary sliding, strain-induced growth and dynamic fragmentation coarse grains in framework theory nonequilibrium boundaries. These are modified for description high-speed flow supplemented by a recrystallization. It shown that materials, sliding dominates material regions with fine-grained submicron structure deforms superplasticity mode. In larger size, volume dominates, accompanied formation size. transformation from coarse-grained occurs due growth. Transformation fine fragmentation. transition at size corresponding optimum value course cyclic change (from deformation) caused alternation processes deformation-stimulated above cycles intragranular different makes it possible maintain high strain suppress both local hardening softening. achieved expense which dominates. dominated deformation, “prepared” superplastic flow.