Optimization on Stir Casting Process Parameters of Al7050/Nano-B4C Metal Matrix Composites

Abstract

Aluminum matrix composites are widely employed in aerospace, military, automobile, and transport applications. The high-strength with low-weight materials are required to fulfill the requirement of high-performance applications. The low-weight materials are reinforced with hard reinforcements to obtain high-strength-to-weight properties for using high-performance applications. The process parameters of fabrication technique define the mechanical and tribological properties. Many types of optimization tools are used for optimizing the process parameters of fabrication method. In this research, the aluminum alloy 7050 and boron carbide are selected as matrix material and reinforcement material. The fabrication of Al7050/B4C composites is produced by the stir casting method. The optimization on stir casting process parameters is done by using the Taguchi approach. The L9 orthogonal array is chosen for this investigation. The chosen input stir casting process parameters are wt% B4C, stirring time (10, 15, and 20 min), stirring speed (300, 350, and 400 rpm), and melting temperature (700, 750, and 800°C). The microhardness is selected as a valuable response parameter for optimizing the stir casting process parameters. The influencing stir casting process parameter sequence is determined by using mean table. The influencing parameters of stir casting on microhardness are stirring speed, stirring time, wt% B4C, and melting temperature. The 9 wt% of boron carbide addition increases the microhardness, and it is higher than the other wt%. The optimum combination of input process parameter combination is 9 wt% boron carbide, 750°C melting temperature, 350 rpm stirring speed, and 15 min stirring time (A3B2C2D2). The percentage of microhardness value improvement is 20.3%.