Creep in crystals with diamond structure

Abstract

A slight modification in the starting equation of the author's earlier model (Ananthakrishna and Sahoo, ibid., vol.14, p.699, 1981) and the use of method of averages leads to expressions for the average dislocation density and the average velocity. The average velocity varies as the square root of the dislocation density. A new creep law is derived which is expected to hold for crystals with diamond structure. It is applied to creep in Si, giving good agreement with experiments. The creep law is cast into a new form in terms of new scaled variables-time and strain scaled with respect to their values at the point of inflection. The scaled creep law is shown to be independent of both temperature and stress for reasonably small initial densities.