New technique for preparing A356 alloy semisolid slurry and its rheo-diecast microstructure and properties
(1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Center International Group Co., Ltd., Beijing 100176, China)
2. Center International Group Co., Ltd., Beijing 100176, China)
Abstract: A new technique for preparing semisolid slurry, namely, distributary-confluence runner (DCR), was combined with die-casting (DC) to conduct rheological die-casting (R-DC) of A356 alloy. The mechanism of DCR for semisolid slurry preparation was determined via numerical simulations and experiments. The microstructure and mechanical properties of A356 alloys prepared via DC and R-DC were studied. High-quality slurry containing numerous primary α-Al (α1-Al) with an average size of 49 μm and a shape factor of 0.81 could be prepared via DCR. Simulation results indicated that the unique flow state and physical field changes during slurry preparation were conducive to accelerating the uniformity of melt temperature and composition fields, nucleation exfoliation, and spherical growth. Compared with the alloy prepared via DC, the tensile strength, yield strength, and elongation of A356 alloy prepared via R-DC increased by 19%, 15%, and 107%, respectively.
Key words: semisolid slurry; A356 alloy; distributary-confluence runner; rheological die-casting; microstructure; tensile properties