熔体冷却速率和热处理对A359铝合金力学性能的影响

The A359 alloy was prepared by lattice-type metal mold with different melt cooling rates, and further treated by T6 heat treatment. On this basis, the effects of melt cooling rate and heat treatment on the mechanical properties of the alloy were investigated. The results indicate that the tensile strength and elongation of the as-cast and T6 treated alloys are increased simultaneously with the increase of melt cooling rate. Furthermore, the influence mechanism of melt cooling rate on the evolution of mechanical properties of the alloy was analyzed combining with the microstructure characterization and the theory of metal strengthening and toughening. The strength and ductility of the A359 alloy are increased simultaneously with the increase of melt cooling rate, which is mainly attributed to the refinement of non-equilibrium solidification microstructure, supersaturated solution of solute atoms, large amounts of nano Si particles in Al matrix and large amounts of nano Al particles in eutectic Si.