EFFECT OF INITIAL TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF CRYOGENIC ROLLED AZ31 MAGNESIUM ALLOY

By characterizing the properties of a twin cast-rolled AZ31 sheet after cryogenic rolling, the effects of the initial temperature on the microstructure and mechanical properties of the sheet obtained by cryogenic rolling were studied. The results indicate that the hardness of the alloy was a maximum due to the high-density dislocations in the microstructure when the initial temperature was room temperature. The highest yield strength and elongation appeared at the initial temperature of 200 °C, and the microstructure was mainly fine equiaxed grains. It was observed that fine grains increased, and the yield strength and elongation gradually decreased with the increase of the initial temperature. The overall trend of yield strength and elongation increased first and then decreased. Based on the results of different initial temperature treatments, the optimal microstructure and properties of AZ31 magnesium alloy were acquired when the initial temperature was 200 °C.