Natural and artificial aging response of semisolid metal processed Al–Si–Mg alloy A356

Abstract

International standards for aluminium alloys often permit significant fluctuations in the content of alloying elements. This allows metal suppliers more freedom in preparing these alloys. It is shown that the magnesium content of semisolid metal processed Al–Si–Mg alloy A356 has a significant influence on the natural and artificial aging behaviour of the alloy. Furthermore, natural aging before artificial aging causes the time to peak hardness (T6) to be longer compared to the time when only artificial aging is used. The optimum quality index in this study was obtained using a short solution heat treatment of 1 h at 540°C, no natural aging and artificial aging at 180°C for 1 h. An increase in the magnesium content of the alloy resulted in an increase in the quality index for all the T6 heat treatment cycles studied.