Computational modeling of titanium structures subjected to thermo-chemo-mechanical environment

Abstract

This manuscript provides a new coupled thermo-chemo-mechanical computational model for titanium structures subjected to extreme loading and environment. The proposed model accounts for the formation of oxygen enriched (alpha-case) titanium, as well as the coupling effects between the response characteristics of mechanical and oxygen infiltration processes into titanium at high temperature environment. The formation of alpha-case at the surface of the structure is modeled as diffusion of oxygen into the titanium substrate. The mechanical response of the structure is idealized using the Johnson–Cook model, which is generalized to account for the effects of oxygen induced embrittlement and hardening. The interplay between mechanical damage, oxygen infiltration and temperature on the chemo-mechanical response is evaluated using numerical simulations. The fully coupled mechanical and diffusion processes are solved based on a staggered coupling algorithm. The capabilities of the computational model are assessed by the analysis of a panel composed of Ti-6Al-2Sn-4Zr-2Mo titanium alloy subjected to thermal shock loading.