Heat Treatment Analysis on Microstructure and Mechanical Properties of Thixoformed Aluminium Alloys

This study investigates the combined effects of magnesium (Mg) content and artificial aging duration on the microstructural evolution and mechanical properties of thixoformed A356 Al–Si–Mg alloys. Magnesium additions of 0.1, 0.3, and 0.5 wt.% were introduced into A356 alloy, followed by thixoforming and T6 heat treatment with artificial aging at 180 °C for 1, 3, and 5 hours. A Taguchi L9 orthogonal array was employed to systematically evaluate the influence of process parameters on yield strength (YS), ultimate tensile strength (UTS), elongation to fracture, and Vickers hardness. The results demonstrate that increasing Mg content and aging duration significantly enhance YS, UTS, and hardness, attributed to precipitation strengthening by Mg₂Si phases and refinement of spheroidized α-Al globules. However, a reduction in ductility was observed with higher Mg levels and prolonged aging. The findings provide an optimized processing window for achieving a balance between strength and ductility in thixoformed A356 alloys, offering practical implications for automotive and lightweight structural applications

A356 Alloy; Thixoforming; Magnesium content; Artificial aging; Mechanical properties; Taguchi method

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