Effect of Sr addition on microstructure evolution and mechanical properties of Zn4%Al hypoeutectic alloy

The effects of Sr in the range of 0-0.15 wt% on microstructure and mechanical properties of ZnAl4 alloy were systematically studied by various characterization methods. It was found that the morphology of primary η-Zn phase and lamellar eutectic varied significantly with increasing Sr content in ZnAl4 alloys, which resulted in the remarkable improvement of mechanical properties. The tensile strength, elongation, impact toughness and HB hardness of ZnAl4 alloys increased with increasing Sr content, peaking at 238 MPa, 5.70%, 74.6 J cm−2 and 82.8 kgf mm−2 with 0.1 wt% Sr, respectively. It can be concluded that the optimal addition of Sr to ZnAl4 alloy may be 0.1 wt% which contributed to finer η-Zn phase and lamellar eutectic. The aim of current study was to provide experimental evidence to establish a correlation between the microstructure and mechanical properties to search for high performance zinc - aluminum die casting alloys.