Investigation of Simultaneous Effects of Cooling Slope Casting and Mold Vibration on Mechanical and Microstructural Properties of A356 Aluminum Alloy

Aluminum alloys are used in numerous industrial fields due to low weight and high strength to weight ratio. Among different forming processes, semi-solid casting is one of the most attractive methods for obtaining improved structures as well as minimizing the porosity and segregation problems of conventional casting. In this study, simultaneous employment of cooling slope and introducing mechanical vibration into the melt during solidification is investigated from viewpoint of microstructure of as-cast A356 aluminum alloy. Obtained results demonstrate that by simultaneous employment of cooling slope and mechanical vibration, more refinement can be occurred in comparison to distinct employment of these two procedures. As a result of this research, in this experimental condition with vibration frequency of 20 Hz and time equal to 3 min, the final average grain size of 50 mu m and shape factor of 0.66 can be achieved. Furthermore, mechanical properties of as-cast alloy are also enhanced so that Brinell hardness number and compression strength of the optimum sample are determined equal to 74 Brinell and 486 MPa, respectively.