Effect of Mg Content on the Shear Strength of Al-Si-Mg and Al-Si-Cu Alloys at Elevated Temperatures

Die soldering in the die casting process is observed as aluminum bonded to the die surface and has historically been associated with Al-Fe intermetallics forming between the molten aluminum alloy and the die steel during the casting process. Researchers have recently identified a new thermomechanical model that rebuts the deep-rooted thermodynamics and kinetics-based theoretical understanding of soldering. This new model accounts for the strength of the aluminum alloy, specifically the shear strength, as a function of temperature. This work fills in the knowledge gap of die cast aluminum shear strength at elevated temperatures observed at the time of part ejection. To further test the model, varying amounts of magnesium were added to A356, A362, and A380 to increase the alloy shear strength. Experimental data shows the shear strength increased as with increasing amounts of magnesium even at higher temperatures.