Phase Diagram of Metals Fragmentation Modes at Severe Plastic Deformation

Considering nonequilibrium evolutional thermodynamics, the approach is developed permitting to describe the process of metal or alloy fragmentation during severe plastic deformation. As a result of an explicit accounting of the main channels of energy dissipation, the basic Gibbs relation is obtained. The concept of state of strongly nonequilibrium system is introduced by means of the expansion of system's thermodynamic potential over independent variables. Using adiabatic approximation the nature of the basic nonequilibrium variables, the Landau-Khalatnikov equation and thermodynamic potential are determined. Carrying out the investigation of stability loss of steady-states of thermodynamic potential, the phase diagram of fragmentation modes of metallic materials is determined. It is shown that defects densities in formed limiting structures correspond to experimentally observed regularities.