Thermodynamics and Multi-physical Model for Application to the Effect of Severe Environment on Metallic Alloys

Abstract

In this paper, we have formulated a fully coupled thermo-elasto-visco-plastic-damage theory, which includes both kinematic and isotropic hardening, and takes also into account the diffusion of several species in metals. This theory is based on the thermodynamics of irreversible processes under small strain hypothesis. Each specie is supposed to diffuse in both lattice and trapping sites. In order to take correctly into account of different coupling effects, the diffusion fluxes vectors depend not only on the gradient of chemical potential, but also on the gradient of temperature (thermodiffusion) and on the gradient of pressure (barodiffusion). The heat flux also depends not only on the gradient of temperature, but also on the chemical potential gradient of each specie, according to the thermodynamics of irreversible processes. This model is implemented into Abaqus/Standard using the Uel user subroutine. An application is made for the diffusion of hydrogen in TA6V after welding.