Effects of the addition of Ca and Sb on the microstructure and mechanical properties of AZ91 magnesium

The microstructure and mechanical properties of AZ91 magnesium with Ca and Sb additives were investigated. Adding 2 wt% Ca refines the microstructure, reduces the amount of the Mg17Al12 phase significantly, and forms a new Al4Ca phase that is reticular in AZ91 magnesium; the tensile strength and elongation properties of the AZ91–2Ca alloys decrease at room temperature (RT). However, with the addition of Ca and Sb, the microstructure is further refined, and a new Ca2Sb phase is formed in AZ91 magnesium with a 0.1%–1.0 wt% Sb addition. Furthermore, the microstructure and mechanical properties of the alloys with the 0.4 wt% Sb addition are found to be optimum.