Development of creep resistant die cast Mg-Sn-Al-Si alloy

Abstract

A study has been made on the tensile properties and high temperature properties of die cast Mg-Sn-Al-Si (TAS831) alloy. The microstructure of TAS831 alloy is characterized by the presence of thermally stable Mg2Sn particles within matrix and along grain boundaries. It also contains a small volume fraction of thermally stable Mg2Si particles. It has been shown that TAS831 alloy has better combinations of tensile properties at room and elevated temperatures than die cast AZ91 alloy. Creep properties of TAS831 alloy are also superior to those of AZ91 alloy. Analyses of creep behavior and load-relaxation behavior at elevated temperatures in the context of internal variable theory indicate that the presence of thermally stable dispersoids in TAS831 alloy increases the resistance to dislocation movement, thereby improving creep properties over those of AZ91 alloy.