Effect of alloy composition on heat resistance and castability of Mg-Al2Ca(Mg) quasi-binary alloys

The effects of the amount of the Al2Ca(Mg) compound on heat resistance and castability of the Mg-Al2Ca(Mg) quasi-binary alloys, the composition ratio of aluminum and calcium of which was 2:1, were investigated. The heat resistance of the Mg-Al2Ca(Mg) quasi-binary alloys was improved by the covering of α-Mg grain boundaries with the Al2Ca(Mg) compound, and more improved by increasing of the amount of the Al2Ca(Mg) compound. The Mg-Al2Ca(Mg) quasi-binary alloys, the compositions of which were close to eutectic one, showed the alloy solidification of the skin-formation type. The duration of the transferred pressure of those molten alloys was long, and the alloys showed the high transfer ability of alloy solidification. It improved the heat resistance and the castability of the Mg-Al2Ca(Mg) quasi-binary alloys for the compositions of aluminum and calcium to be closer to eutectic.