Identifiying creep mechanisms at low stresses

There are three possible mechanisms occurring in high temperature creep at low stresses: diffusion creep, Harper–Dorn creep and grain boundary sliding. This paper examines the characteristics of these three processes and proposes two sets of measurements that may be used to give an unambiguous identification of the dominant creep mechanism. The approach is applied to published creep data and new measurements are reported for a Mg–0.55%Zr alloy which permit a clear distinction between diffusion creep and grain boundary sliding.