The Effect of Trace Addition of Strontium and Zinc on the Creep Properties of Mg-6Sn-5Al-2Si Alloys

Abstract

Mg alloys containing Mg₂Si and Mg₂Sn phases are promising inexpensive heat-resistant magnesium alloys for automobile engine applications. This study examined the microstructure and creep properties of Mg-6Sn-5Al-2Si alloys. The microstructures of these alloys were characterized by the presence of thermally stable Mg₂Si and Mg₂Sn and thermally unstable Mg₁₇Al₁₂ precipitates. Creep tests were performed at 30, 50 and 70 MPa at 150, 180 and 200°C. Trace amounts of Sr and Zn were added to these alloys to improve the mechanical properties by modifying the precipitates in the matrix. The influence of the combined addition of Sr and Zn on the microstructure and mechanical properties was also studied. Analyses of the mechanical properties indicated that Sr and Zn addition improved the tensile strength but decreased the creep resistance.