Effect of heat treatment on fracture surfaces in recycled aluminium cast alloy

Abstract

Recycled AlSi9Cu3 cast alloy was heat treated by solution treatment at temperature 515 °C (4 hours), quenched and artificial aged at temperatures 130 °C,  170 °C and 210 °C (2, 4, 8, 16 and 32 hours). Heat treatment led to spheroidization of eutectic Si, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of Cu-rich phases and the precipitation of finer hardening phase (Al2Cu). The change of morphology of structural components significantly affects the fracture surface of Al-alloy. The fracture morphology changes gradually from dominant brittle transcrystalline cleavage fracture to ductile fracture with numerous small dimples (locally presence the cleavage fractures of Fe-rich phases).