Effect of Strontium Addition on the Microstructures and Mechanical Properties of Mg-5Al-3Ca Alloys

Abstract

The effect of adding up to 4 mass% of strontium to Mg-5Al-3Ca alloys was investigated in terms of microstructural and mechanical properties. The major interdendritic intermetallic compounds of as-cast alloys changed from the Mg₂Ca phase to a combination of the (Mg,Al)₂Ca and Al₄Sr phases. The morphology of the interdendritic α-Mg/Al₄Sr eutectic phase also changed from a coarse lamellar structure at a low strontium concentration to a bulk-like ultrafine lamellar structure at a high strontium concentration (4 mass%). The creep resistance was improved by the addition of up to 2 mass% strontium but it was saturated at a higher strontium concentration.