The grain size dependence of flow stress in an ECAPed AZ31 Mg alloy with a constant texture

ECAPed Mg sample with a smaller grain size showed a lower yield stress compared to a unECAPed (as-extruded) sample with a large grain due to texture modification during ECAP process. An equation for the flow stress of an ECAPed alloy with a constant texture as a function of the strain and grain size was derived to quantify the effect of the grain size on the flow stress in this alloy, assuming that 2-, 3-, and 4-passed microstructures have the same texture. According to the predicted flow stress results, the strain hardening is the largest contributor to flow stress and that the solid solution hardening and grain size refinement play relatively minor roles on flow stress in ECAPed samples.