Tensile properties and fracture behavior of partial squeeze added slow shot die-cast A356 aluminum alloy

In this contribution, effect of the microstructural characteristics on tensile properties and fracture behavior of partial squeeze added slow shot die-cast A356 alloy die casting in the as-cast and T6 heat-treated conditions was studied. The results show that, inferior tensile properties of the casting partial squeeze part were caused by the heterogeneity of α-Al cells with fragment, rosette, angular and globular shapes, while finer dendrites with smaller secondary dendrite arm spacing and more rounded silicon particles corresponded to higher tensile properties. After T6 treatment, tensile properties increased significantly, due to the spheroidization of silicon particle and consequently the reduction of stress concentration at silicon/eutectic matrix interface. Differences observed in the tensile fracture path were attributed to microstructural changes as well as morphological aspects of silicon phase.