Stir Casting Process Parameters and Their Influence on the Production of AA6061/B4C Metal Matrix Composites

Abstract

AbstractStir casting process is a simple yet economic process for the production of metal matrix composites. The present study primarily focuses on the production and characterization of aluminium-based matrix composite (AA 6061 reinforced B4C) in the stir casting process. Many factors influence the effective production of aluminium-based metal matrix composites. In good composites, the reinforcement particles are uniformly dispersed throughout the base metal facilitating greater ultimate strength and hardness. In this regard, the input parameters considered are:- holding temperature, stirrer speed, stirring time and percentage of reinforcement. The response variables considered are the tensile strength and the Brinell hardness of the composites. Response surface methodology with full factor central composite design is incorporated for the determination of optimal values. A mathematical model is developed for mapping the input stir casting parameters with output response variables. The significance of the model is ensured with ANOVA and regression analysis. The influence of stirring time, holding temperature, percentage of reinforcement and stirrer speed on tensile strength and hardness is discussed using a 3D surface plot. The uniform dispersal of the reinforcement particles among the matrix is ensured by scanning it with an electron microscope and through EDAX analysis of the produced AA6061/B4C composites. Fabricated composite specimens are subjected to tensile test and Brinell hardness test. Tensile strength of composites is influenced by stirrer speed and stirring time. Stirrer speed and weight percentage of reinforcement play a vital role in the hardness of the composite. Uniform dispersion with optimal tensile strength and hardness is achieved at the stirrer speed of 360 rpm, stirring time of 8 min with the holding temperature of 700 ℃ in the 7.5% of B4C reinforcement composites.KeywordsAluminium metal matrix compositesStir castingMicrostructureTensile strengthHardness