Effect of Strontium Modification on Microstructure and Mechanical Property Al12SiCuMgNi Alloy in Squeeze Casting

Abstract

Abstract The Al-Si series alloys, which have excellent fluidity and castability, are the most common aluminum material in the casting industry. However, the coarse eutectic Si phase with laminar morphology leads to the stress concentration of material and has a detrimental effect on the mechanical properties of aluminum alloy components. In this study, the Strontium (Sr) modifier was added to Al12SiCuMgNi alloy and the effect of Sr on microstructure and performance of Al12SiCuMgNi in squeeze casting was investigated. The experimental results show that the eutectic Si phase was well modified to fibrous morphology. Although the yield strength (YS) was leveled, the ultimate tensile strength (UTS) and elongation (EL) of the alloy were obviously enhanced after Sr addition. When the 0.012wt.% Sr was added to Al12SiCuMgNi alloy. The YS, UTS, and EL of alloys were up to 311 MPa, 401 MPa, and 3.4%, respectively. Moreover, the microstructure and performance of Al12SiCuMgNi alloy in the hot forging process were also compared to Al12SiCuMgNi alloy with and without Sr addition in squeeze casting. It is concluded that the Al12SiCuMgNi alloy in hot forging shows higher ductility (4.7%) and lower strength than Al12SiCuMgNi alloy in squeeze casting.