Effect of Ageing Temperature on the Mechanical Properties of Al-6Si-0.5Mg Cast Alloys with Cu Additions Treated by T6 Heat Treatment

Effect of artificial ageing temperature on the mechanical properties of Al-6Si-0.5Mg alloy containing 0.5 – 4 wt% Cu was studied. The solution treated alloys containing different amounts of Cu were aged isochronally for 1 hour at temperatures up to 300C. The precipitation stages during ageing were monitored by hardness measurements. Tensile and impact properties were determined by standard tests. During artificial ageing, the yield and ultimate tensile strengths were found to increase with ageing temperature; the maximum being attained at peak aged condition. Ductility and impact toughness of the alloys, on the other hand decreased with ageing temperature reaching the minimum at the highest hardness. The addition of Cu resulted in an increase in hardness and tensile strength and substantial reduction of ductility and fracture toughness.