Combining Phenomenology and Physics in Describing the High Temperature Mechanical Behavior of Crystalline Solids

Abstract

It is now possible to predict quantitatively the high temperature mechanical behavior of pure metals, solid solution alloys and dispersion hardened alloys, based on an understanding of a number of physical factors influencing power law creep, including: (a) atom mobility by lattice diffusion and by dislocation pipe diffusion, (b) elastic constants of the matrix material, (c) subgrain size, (d) stacking fault energy, and (e) crystallographic texture. This quantitative picture can be extended and generalized to transient situations using the work hardening-recovery approach, and strengthening due to back stresses, solutes, and irradiation can be incorporated within the same framework. The resulting set of constitutive equations for creep rests on a firm physical foundation and yet can predict the high-temperature behavior of materials under the complex histories typical of technological applications.