A model for microstructure evolution in adiabatic shear bands

A mechanical subgrain rotation model is proposed to account for the recrystallized grains which have been observed to form in adiabatic shear bands in a number of materials. The model is based on a "bicrystal" approach using crystal plasticity theory to predict the evolution of subgrain misorientations. These mechanically induced rotations are shown to occur at the high strain rate associated with adiabatic shear band formation. Recrystallized grain formation is proposed to occur by the formation and mechanical rotation of subgrains during deformation, coupled with boundary refinement via diffusion during shear band cooling. This model is referred to as progressive subgrain misorientation recrystallization and appears to account fdr shear band microstructures in a variety of metals.