Influence of high pressure and manganese addition on Fe-rich phases and mechanical properties of hypereutectic Al-Si alloy with rheo-squeeze casting
(1. Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety, Wuhan Institute of Technology, Wuhan 430205, China;
2. State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China)
2. State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China)
Abstract: The influence of high pressure and manganese addition on Fe-rich phases (FRPs) and mechanical properties of Al-14Si-2Fe alloy with rheo-squeeze casting (RSC) was investigated. The semi-solid alloy melt was treated by ultrasonic vibration (UV) firstly, and then formed by squeeze casting (SC). Results show that the FRPs in as-cast SC alloys are composed of coarse β-Al5(Fe,Mn)Si, δ-Al4(Fe,Mn)Si2 and bone-shaped α-Al15(Fe,Mn)3Si2 phases when the pressure is 0 MPa. With RSC process, the FRPs are first refined by UV, and then the solidification under pressure further causes the grains to become smaller. The peritectic transformation occurs during the formation of α phase. For the alloy with the same composition, the ultimate tensile strength (UTS) of RSC sample is higher than that of the SC sample. With the same forming process, the UTS of Al-14Si-2Fe-0.8Mn alloy is higher than that of Al-14Si-2Fe-0.4Mn alloy.
Key words: high pressure; manganese; rheo-squeeze casting; hypereutectic Al-Si alloy; Fe-rich phases; mechanical properties