Phenomenological equation for the thermal dependence of the activation energy of creep

A phenomenological equation to model the variation with temperature of the activation energy of creep at high temperature is proposed. This equation expresses the activation energy of the creep as a function of both the metal's high-temperature self-diffusion energy and the relative temperature. The proposed expression considers three fitting parameters, whose roles and typical values are described. The expression is validated with bibliographic data referred to creep experiences carried out on pure polycrystalline specimens of copper, aluminium and silver. Additionally, the proposed expression allows computing the integral mean value of the activation energy for a determined temperatures interval. The obtained results can clearly be of interest to simulate processes under creep or hot deformation conditions.