Microstructure and Tensile Properties of Mg-4Zn-2Sn-2Al Alloy

摘要

The microstructures and tensile properties of as-cast, solution-treated and aged Mg-4Zn-2Sn-2Al(wt.%) alloy have been investigated. The microstructure of the as-cast alloy consists of a-Mg, Mg_2Sn and Mg_(32)(Al,Zn)_(49) phases. The yield tensile strength and the ultimate tensile strength of the as-cast alloy are 87.7 MPa and 241.3 MPa, respectively, and the elongation reaches to 18.8% showing excellent ductility. After solution treatment, all of the Mg_(32)(Al,Zn)_(49) phase and the majority of Mg_2Sn particles have dissolved into the matrix. During aging process, Mg_2Sn phase precipitates from the a-Mg supersaturated solid solution. With the precipitation strengthening of Mg_2Sn phase, the yield tensile strength and the ultimate tensile strength of the alloy increase to 112.5 MPa and 280.4 MPa, respectively, while, the elongation decreases to 12%.