材料期刊网

This experimental study was conducted to investigate the effect of melt cleanliness with respect to the presence of inclusions on the mechanical properties of AZ31 alloy. The type, morphology and size distribution of inclusions in the alloy were analysed. The tensile properties of the AZ31 alloy with and without melt purification were tested at room temperature. The fracture surface of the AZ31 alloy was observed by SEM to reveal the mechanism of fracture nucleation. By melt purification treatment, most of the inclusions are removed from the AZ31 alloy, and the average size of inclusions in the alloy is decreased from 16.5 to 2.0 mu m. In addition, the tensile strength and especially the elongation of the alloy are increased. Tensile fracture analysis showed that the inclusions act as crack initiation sites during fracture. The MgO film, which is the main inclusion in the alloy, contributed to poorer mechanical properties.