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 70MPa 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. © 2009 The Japan Institute of Metals.