Life prediction under tension of titanium alloys that develop an oxygenated brittle case during use

A simple model was used to predict the tendency of an (alpha + beta) titanium alloy to crack under tension after exposure to air at temperature. The model was experimentally validated for minimum stress to crack and saturation crack spacing. A diffusion model for oxygen ingress as a function of time, temperature and oxygen partial pressure is outlined; together with the surface cracking model and empirical crack growth models, this enables the framework for a life prediction tool for arbitrary time-temperature-environment history. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.