Creep fracture by coupled power-law creep and diffusion under multiaxial stress

Abstract

Creep fracture by coupled diffusion and power-law creep is analysed, using approximate methods, both for uniaxial tension and for axial tension plus a superimposed hydrostatic tension. Over a wide range of stress and temperature voids grow predominantly by diffusion when they are small and by power-law creep when they are large, so that the time to fracture is determined by a contribution from each mechanism. A change of temperature, stress, or stress state changes the relative contribution of each mechanism. The equations for void growth are integrated to give both the times and strains to fracture.