Microstructure and Mechanical Properties of Magnesium Alloy Prepared by Repetitive Upsetting
Repetitive upsetting (RU) was applied to a commercial AZ31 Mg alloy. The samples were processed at temperatures of 230 °C, 250 °C and 300 °C up to 3 passes. Effects of processing temperature on the microstructure and mechanical properties were investigated. The results indicate that the microstructure was effectively refined by RU and an average grain size of ~1.9 μm was obtained at 250 °C. Increasing the temperature resulted in larger mean grain size and higher microstructural homogeneity. Both the strength and hardness were significantly improved. It was also found that increasing the processing temperature led to increase in the strength but decrease in the ductility. The sample after RU 3 passes at 230 °C had tensile strength of 330 MPa compared with 173 MPa prior to the processing.