UNIFIED THERMODYNAMIC TREATMENT OF CAVITY NUCLEATION AND GROWTH IN HIGH-TEMPERATURE CREEP

Existing models describing the creep nucleation and growth are briefly outlined in orderss to obtain a starting point for a new physical framework which unifies the stochastic treatment of nucleation with the deterministic treatment of growth. For this purpose an original hypothesis was postulated to develop the equations of motion of a thermodynamic system in non-equilibrium state at constant temperature and pressure. It is shown the application of this hypotthesis to a system of creep cavities provides the unified equations describing the evolution of cavities during their nucleation and growth stages. Particular attention is devoted to the role of the elastic relaxation of local normal stress due to deposition of atoms from a cavity its nucleation. © 1990.