한국주조공학회

Aluminium alloy castings, which can be not only manufactured in larger geometrically complex shapes, but also show good mechanical properties in addition to light weight, have kept their potential use as structures in the field of automotives, industrial machines and aircrafts. The variations of eutectic Si size a great effect on the elongation, impact value, fracture toughness and fatigue crack propagation rate without changes in the tensile strength or yield strength. The cooling curves with the solidification rate between 1.4^℃/min and $19.1^℃/min were obtained. With the increase of solidification rate, DAS, eutectic Si size and grain size were all decreased, which enhanced the mechanical properties. The tensile strength and yield strength were the most greatly influenced by DAS, and the elongation and impact value by eutectic Si size.