A study on the composition optimization and mechanical properties of Al–Mg–Si cast alloys

The mechanical properties of Al–Mg–Si cast alloys with different chemical compositions were investigated using an orthogonal test method. The optimized chemical compositions of Al alloy are given in wt% as follows: 7.0%Si–0.35%Mg–2.0%Cu–0.2%Mn–0.2%Ni–0.1%V–0.8%RE–89.35%Al. The optimized Al–Mg–Si alloy with metal mold casting had excellent mechanical properties. The softening resistance of the optimized alloy was better than that of ZL101 at elevated temperatures. The scanning electron microscopy fractographs of the tensile samples of ZL101 and optimized Al alloy at different magnifications revealed that all the specimens were fractured in a ductile manner, consisting of well-developed dimples over the entire surface. The alloys failed in a mixed-mode fracture, comprised predominantly of transgranular shears and a small amount of quasi-cleavages.