Influence of Sb modification on microstructures and mechanical properties of Mg2Si/AM60 composites

The refining effect and mechanism of Sb on Mg2Si and the microstructure of the matrix were investigated. The results indicate that there are Mg3Sb2 particles in the composites with the addition of Sb, and Mg3Sb2 can promote the formation of fine polygonal type Mg2Si by providing nucleation site. Meanwhile, the grain size of Sb modified alloy is finer than that of the matrix. The improved microstructure results in the improvement of mechanical properties. The ultimate tensile strength is increased by 12.2% with the addition of 0.8% Sb.