Microstructure and fatigue properties of the ultrafine-grained AM60 magnesium alloy processed by equal-channel angular pressing

Abstract This paper reports on the microstructures and fatigue properties of the ultrafine-grained AM60 magnesium alloy processed by equal-channel angular pressing (ECAP) at various temperatures. After ECAP processing, samples exhibited an increase in fatigue endurance limit, which correlates well with a decrease in grain size. For the lowest ECAP temperature, the mean grain size is as small as 1 μm which leads to an increase in the fatigue endurance limit by 70% in comparison to coarse-grained alloy. The temperature of ECAP not only governs the grain size but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.