Effects of cooling rate on microstructure and mechanical properties of A357 alloy during differential pressure casting process
(1.黑龙江省哈尔滨市哈尔滨工业大学材料科学与工程学院2.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: The microstructure and mechanical properties of A357 alloy under differential pressure casting process with different casting mould materials were studied. The results show that by using SiO2 resin sand the grain size is biggest and the tensile and elongation are the lowest, while the grain size is the smallest and the tensile strength and elongation are the highest when the chill is used, and the grain size, tensile strength and elongation of A357 alloy with SiC resin sand mould are in the middle. Furthermore, the results also demonstrate that for thin wall castings during differential pressure casting processes the grain size, tensile strength and elongation are different at different positions corresponding to the same casting mould material, while at the position of gating the grain size is the smallest and the tensile strength and elongation have the highest values. At the position of edge the grain size, the tensile strength and elongation take the second place. However, in the middle of the thin wall castings the grain size is coarsest and the tensile strength and elongation are the lowest.
Key words: A357 alloy； different pressure casting； cooling rate； mechanical properties