Effect of T6 heat treatment on corrosion resistance and mechanical properties of AM50 magnesium alloy

Abstract

To improve the corrosion resistance and mechanical properties of AM50 magnesium alloy, T6 heat treatment was applied. The microstructure, mechanical properties and corrosion properties of as-cast and T6 heat-treated alloy were studied. The results indicated that the β phase presented at the grain boundaries along with Al–Mn phase after T6 heat-treatment. Because of solid solution and aging treatments, the tensile strength of the AM50 magnesium alloy was increased. The decreasing of the β phase owing to the solidsolution during T6 treatment, which causes Al solid solution in the α-Mg phase, and it is favourable for increasing the corrosion resistance of AM50 magnesium alloy. The fracture mechanisms of the as-cast and T6 heat-treated alloy were quasi-cleavage fracture. The corrosion residual strength of the T6 heat-treated alloy was higher than that of the as-cast alloy. Compared with the as-cast alloy, the corrosion rate of the T6 heat-treated alloy decreased gradually.