A Review of Different Creep Mechanisms in Mg Alloys Based on Stress Exponent and Activation Energy

Magnesium being the lightest structural material, is being increasingly used in automotive industry but at elevated temperatures, alloys like AZ91D, AM60B, AM50A etc. exhibit poor creep resistance which hinders the powertrain applications. This article summarizes the various creep deformation mechanisms prevailing in magnesium alloys at elevated temperatures by the influence of elemental additions. The main creep mechanisms are found to be dislocation climb, diffusion creep, and grain boundary sliding. The variation of creep mechanisms for different Mg alloys with respect to the activation energy (Q), stress exponent (n) for different stresses and temperatures are reported.