Abstract: Generally, permanent mould cast Al-Mg alloys are not heat treatable, but the addition of Zn in this alloy could render it heat treatable. It could be expected that in its as-cast state (F temper condition) there should be non-equilibrium intermetallic remaining at grain boundaries after casting which could be detrimental to corrosion properties of the alloy. This study investigated the effect of heat treatment and artificial ageing of Al-5Mg-2Zn. The study showed intermetallic phases at the grain boundaries and a melting peak at about 476 °C for the F condition. Solution heat treatment at 440oC for 4 hours dissolved the intermetallic phase thus increasing the melting point of the alloy. The results further showed an appreciable increase of mechanical properties after T6 heat treatment over the F-condition.
Authors: Levy Chauke, Ulyate Curle, and Gonasagren Govender
Keywords: Heat Treatment, Al-Mg-Zn, Artificial Ageing