Effects of Y on Microstructure and Mechanical Properties of As-cast AZ31 Magnesium Alloy

AZ31 magnesium alloy was prepared in vacuum melting furnace.The alloy's microstructure and mechanical properties were studied,and precipitation phase was analyzed in a way to improve the alloy's mechanical properties.The results show that yttrium(Y) exists as the form of compound(Al2Y) in AZ31 magnesium alloy, and dystectic Al2Y as the heteromorphic nucleation emerges firstly in the course of alloy precipitation,which refines the alloy's microstructure and obviously improves the mechanical properties at room and high temperature.The average grain size of AZ31 magnesium alloy containing Y is reduced by 35.82%.Tensile strength,yield strength and elongation percentage reach 212 MPa,147 MPa,and 7.5% at room temperature respectively,and 117 MPa,98 MPa,and 10.2% at 200 ℃ respectively.