Optimization of Stirring Speed and Time in Achieving Sound A356-Sic MMCs and its Effects on Microstructure and Mechanical Properties

Abstract

Stirring is an essential and important factor in stir casting process of Liquid Metallurgy (LM) to achieve homogeneous dispersion of the reinforcements in the matrix. In the present study two important parameters of stirring, such as stirring time and speed were optimized for the preparation of sound A356-SiC Metal Matrix Composites (MMCs). The effect of stirring speed and time on microstructure of A356-10%SiC MMCs were analyzed using Scanning Electron Microscopy (SEM), Energy- dispersive X-Ray Spectroscopy (EDX) and X-Ray Diffractometry (XRD). The experiments were carried out for different stirring speed and time varying from 250, 350, and 450 rpm and 5, 7, and 9 minutes respectively. Initially stirring time was optimized and was found to be 7 minutes at a constant stirring speed of 350 rpm. And this optimized stirring time of 7 minutes is considered for further experiments while optimizing stirring speeds. Increase in the stirring speed and time from 5 minutes and 250 rpm resulted in homogeneous distribution of SiC particles in A356 matrix without having any agglomeration or segregation. Further, at the stirring speed of 350 rpm and stirring time of 7 Minutes a sound A356-SiC MMCs were obtained. Increases in stirring speed and time, on the other hand, resulted in the loss of microstructural characteristics. Finally, a stirring speed of 350 rpm and a stirring period of 7 minutes were discovered to be the ideal speed and time for achieving maximal tensile strength and hardness.