Effect of Alloying Elements on the Microstructural Evolution of Mg-Sn Based Cast Alloys

Abstract

A study has been made on the effect of Sb and Sr on the microstructure and mechanical properties of Mg-Sn-Al-Si based (TAS) alloy. When Sb is added more than 3 wt.%, Mg3Sb2 particles acted as nucleation sites for Mg2Si and Mg2Sn particles. Increased volume fraction and decreased shape factor of the particles improved the hardness of the alloys. When Sr is added, a few kinds of particles. such as rod-like MgSi2Sr, SiSr2 and polygonal Sr5Sn3 particles are formed within the microstructure. Large volume fraction and uniform distribution of the particles greatly improved the hardness of the alloys. These microstructural changes by Sb, Sr addition are also expected to have beneficial effect on the room and high temperature mechanical properties.