Effect of grain size on high temperature deformation of AZ31 alloy

The effect of grain size on the high temperature mechanical response of the AZ31 magnesium alloy has been investigated by a comparative analysis of the data obtained in the present study and of several other literature results. The basis of the analysis was a phenomenological description, which took into account the existence of two well defined regimes, the first characterized by a n = 3 stress exponent, and the second described by a modified form of the Garofalo equation, indicating the transition from a viscous-glide to climb as rate controlling mechanisms. The description was modified by introducing a further parameter, the grain size; after this correction, the resulting equations were found to give an excellent description of the weak but non-negligible effect of the grain size on the creep response of the alloy.

► Creep response between 100 and 300 °C of a AZ31 magnesium alloy.
► Grain size has a moderate but non-negligible effect on creep rate.
► The effect is described by introducing the grain size term in a previously developed model.
► Concentration of aluminium in solid solution and grain size are taken into account in the model.