Aging temperature and abrasive wear behaviour of cast Al–(4%, 12%, 20%)Si–0.3% Mg alloys

In the present paper, influence of aging temperature during artificial age hardening treatment (T6) of cast Al–(4, 12, 20%)Si–0.3% Mg on abrasive wear behaviour has been reported. Alloys were prepared by controlled melting and casting. Cast alloys were given age hardening treatment having sequence of solutionizing, quenching and artificial aging. All the alloys were solutionized at 510 °C for 8 h followed by water quenching (30 °C) and aging hardening at 150, 170, 190, 210 and 230 °C for 12 h. Abrasive wear tests were conducted against of 320 grade SiC abrasive medium at 5 and 10 N normal loads. It was observed that the silicon content and aging temperature significantly affect the wear resistance. Increase in aging temperature improves the wear resistance. Hypereutectic alloy showed better wear resistance than the eutectic alloy under identical conditions. Optical microstructure study of alloys under investigation has shown that cast dendritic structure is destroyed besides the spheroidization of eutectic silicon crystals after the heat treatment. The extent of change in structure depends on aging temperature. Scanning electron microscopy (SEM) of wear surface was carried to analyze the wear mechanism.