Effects of minor Sr, Sn and Sc addition on as-cast microstructure and
mechanical properties of ZA84 magnesium alloy
(1. Materials Science and Engineering College, Chongqing University of Technology, Chongqing 400050, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030, China)
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030, China)
Abstract: The effects of minor Sr, Sn and Sc addition on the as-cast microstructure and mechanical properties of the ZA84 magnesium alloy were compared. The results indicate that addition of 0.1%Sr, 0.5%Sn or 0.3%Sc (mass fraction) to the ZA84 alloy can refine the grains of the alloy. Furthermore, addition of 0.1%Sr to the ZA84 alloy does not obviously change the morphology and distribution of Mg32(Al,Zn)49 phase. However, addition of 0.5%Sn or 0.3%Sc not only refines and modifies the Mg32(Al,Zn)49 phase but also suppresses the formation of Mg32(Al,Zn)49 phase, especially with the addition of 0.3%Sc. Furthermore, addition of 0.1%Sr, 0.5%Sn or 0.3%Sc to the ZA84 alloy improves the tensile properties at room temperature and 150 ˚C, especially with the addition of 0.1%Sr and 0.3%Sc. However, addition of 0.1%Sr is not beneficial to the creep properties, and addition of 0.5%Sn has no obvious influence on the creep properties. Oppositely, addition of 0.3%Sc to the ZA84 alloy greatly improves the creep properties.
Key words: magnesium alloy; ZA84 magnesium alloy; Sr; Sn; Sc