Improving low-cycle fatigue properties of rolled AZ31 magnesium alloy by pre-compression deformation

Abstract

The effect of pre-compression deformation on the low-cycle fatigue properties and cyclic deformation behavior of as-rolled AZ31 alloy was investigated by performing the stress-controlled low-cycle fatigue tests at room temperature. Fatigue properties and cyclic damage process should be closely related to the twins. The present work aimed to investigate the deformation mechanism and fatigue life caused by the introduced {10−12} twinning–detwinning from the viewpoint of stress amplitude. The results reveal that the twins contribute to the fatigue properties and cyclic damage process of AZ31 alloy. There were noticeable changes in hysteresis loops, microstructures and fatigue lives when the stress amplitude increased from 120 to 150MPa. The fatigue life of pre-compressed samples was more superior to that of the as-rolled sample under different stress amplitudes, especially under the stress amplitude close to the tensile yield strength of the as-rolled sample.