Microstructure and mechanical properties of rheo-diecasted A390 alloy

The microstructure and mechanical properties of the rheo-diecasting (RDC) A390 alloy under as-cast and T6 heat treatment conditions were investigated. The results indicate that the RDC sample has fine and uniform microstructure throughout the sample under the as-cast condition, and the average size of primary Si spheroids is 20-30 μm. Meanwhile, the intermetallic compounds in RDC sample are reduced. Compared with the alloy produced by conventional liquid die-casting(LDC), RDC samples have improved tensile strength, ductility, hardness and wear resistance. It is also found that heat-treatment of the RDC A390 alloy under T6 condition, can substantially improve mechanical properties, with the tensile elongation more than 100% improvement.