A CONTINUUM-MECHANICS THEORY OF MICROSTRUCTURE FORMATION IN DEFORMED SOLIDS

Ductile solids are strongly dissipative, non-linear systems for which instability transitions and selforganization effects are typical. A convenient framework for description of these phenomena is provided by Asaro et al.'s model of a ductile crystal where densities of stored dislocations are introduced as additional field variables. It is shown that inelastic properties are governed by two types of instability transitions. The first leads to selforganization in the form of a deformation microstructure. The second type causes shear banding and misorientation of the crystal lattice which modify microstructure and may initiate rupture processes. The suggested theory indicates that inelastic properties of ductile solids are consequences of a competition between these instability processes.