Microstructure, Tensile Properties, and Corrosion Behavior of Die-Cast Mg-7Al-1Ca-xSn Alloys

The microstructure, tensile properties, and corrosion behavior of die-cast Mg-7Al-1Ca-xSn (x = 0, 0.5, 1.0, and 2.0 wt.%) alloys were studied using OM, SEM/EDS, tensile test, weight loss test, and electrochemical test. The experimental results showed that Sn addition effectively refined grains and intermetallic phases and increased the amount of intermetallic phases. Meanwhile, Sn addition to the alloys suppressed the formation of the (Mg,Al)₂Ca phase and resulted in the formation of the ternary CaMgSn phase and the binary Mg₂Sn phase. The Mg-7Al-1Ca-0.5Sn alloy exhibited best tensile properties at room temperature, while Mg-7Al-1Ca-1.0Sn alloy exhibited best tensile properties at elevated temperature. The corrosion resistance of studied alloys was improved by the Sn addition, and the Mg-7Al-1Ca-0.5Sn alloy presented the best corrosion resistance.