MODEL FOR THE HIGH-TEMPERATURE EMBRITTLEMENT OF METALS CONTAINING HELIUM

A model for the high-temperature embrittlement of He-containing metals is presented. The model is based on the formation of small He bubbles within the grains and on the nucleation and growth of grain-boundary cavities under the influence of He and external stress. These processes explain the strengthening of the grains and the simultaneous weakening of the grain boundaries. After a careful analysis of nucleation and growth of grain-boundary cavities, an analytical expression for the time to rupture as a function of stress, He content, temperature and material parameters is derived. This expression is in satisfactory agreement with experimental data for He-implanted stainless steel samples (Sagüés, Schroeder, Kesternich and Ullmaier 1978). © 1979 Taylor & Francis Group, LLC.