This research program investigates inelastic deformation processes in metals. Research in the program examines microstructural changes occurring in a solid during deformation under a range of operating environments (primarily elevated temperatures) and stress/strain rate conditions. Model alloy systems being studied include aluminum, copper, type 304 stainless steel, and a series of nickel-cobalt alloys. The selected systems allow important deformation parameters such as stacking fault energy to be investigated. Primary objectives of this research are (1) to develop a quantitative description of the kinetics of deformation and the evolution of microstructure and (2) to formulate constitutive models of deformation for engineering applications.