Constituent Diffusion in a Deformable Thermoelastic Solid

Abstract

Solid mixtures containing initially uniform dilute concentrations of impurity elements may, upon the application of mechanical and thermal loading, develop regions of high impurity concentration that could result in local degradation of material properties. To address these degradation processes, a fully coupled thermomechanical-diffusion theory has been developed to describe the mass transport of mobile constituents driven by gradients in concentration, strain dilatation and temperature in a solid deformable parent material. A finite element code has been assembled to solve plane transient thermomechanical-diffusion problems. The theory presented and the resulting code have been successfully used to model internal hydrogen redistribution in β-phase Ti alloys induced by elastic strain gradients during bending.