Impact of stir-squeeze casting process parameters on tensile strength of hybrid aluminium matrix composite

Abstract

Aluminium metal matrix composite with higher tensile strength is made using a hybrid stir-squeeze casting technique. The hybrid technology combines the desirable features of uniform reinforcement particle distribution in the base matrix through stir casting and refined microstructure, minimizing porosity and enhanced mechanical properties via squeeze casting process. The composite was made from A356 aluminium alloy reinforced with Molybdenum disulfide (MoS2) and wheat husk ash (WHA). A356 alloy has a wide range of engineering applications, with MoS2 increasing wear resistance and WHA particles providing major technological and economic benefits. Taguchi L16 orthogonal array experiments are applied to optimize the stir-squeeze casting parameters (stirring speed, mould temperature, squeeze time squeeze pressure, pouring temperature) for achieving better tensile strength of the composites. The identified significant factors for the stir-squeeze casting process are stirring speed, squeeze pressure, and squeeze time. The optimum stir-squeeze casting condition increased the composite's tensile strength by 23.72%. The squeeze pressure of 125 MPa was noted that to eliminating these porosities and gives better grain refinement in the microstructure. The fractured tensile test specimen indicated the brittle and ductile mode of fracture.