Constitutive Theories for Solids with Defective Microstructure

The nonlinear mechanical response of solids is a macroscopic manifestation of the irreversible changes in its microstructure. The most common modes of the irreversible microstructural rearrangements are crystalline slip, twinning, diffusional flow, change of phase, change in porosity and loss of cohesion along the grain boundaries or cleavage planes. The degree to which a particular mode contributes to the rate at which the energy is dissipated is macroscopically reflected as the degree of ductility. Refs.