Effects of Sn addition on as-cast microstructure, mechanical properties and casting fluidity of ZA84 magnesium alloy

The effects of Sn addition on the as-cast microstructure, mechanical properties and casting fluidity of the ZA84 magnesium alloy are investigated. The results indicate that adding 0.5–2.0 wt.%Sn to the ZA84 alloy not only can result in the formation of Mg2Sn phase but also can refine the Mg32(Al, Zn)49 phase and suppress the formation of Mg32(Al, Zn)49 phase, and with the increase of Sn amount from 0.5 wt.% to 2.0 wt.%, the morphology of Mg32(Al, Zn)49 phase gradually changes from coarse continuous and/or quasi-continuous net to relatively fine quasi-continuous and/or disconnected shapes. In addition, adding 0.5–2.0 wt.%Sn to the ZA84 alloy can improve the tensile and creep properties, and casting fluidity of the alloy. Among the Sn-containing ZA84 alloys, the ZA84 alloy added 1.0 wt.%Sn exhibits the best ultimate tensile strength, elongation and casting fluidity while the ZA84 alloy added 2.0 wt.%Sn has the best yield strength and creep properties.