THERMAL CAVITY NUCLEATION AT INTERGRANULAR INCLUSIONS IN HIGH-TEMPERATURE CREEP

The role of intergranular inclusions at the thermal cavity nucleation in high temperature creep is analysed in detail. The theoretical treatment is generalized for cavities the free surface curvature radius of which is comparable with the inclusion size and for cavities forming with inclusions the equilibrium systems. Special attention is devoted to the influence of the interface energies, the inclusions volume and the internal stress concentrations to the cavity nucleation kinetics. Each kinetics of cavity nucleation observed is qualitatively explained on the basis of the thermally activated heterogeneous cavity nucleation at intergranular inclusions. © 1990.