Role of homogeneous distribution of SiC reinforcement on the characteristics of stir casted Al–SiC composites

Abstract

Stir casting process is very popular for the fabrication of particle reinforced metal matrix composites. However, achieving a homogenous distribution of the reinforcement particles is very challenging, which directly affect the final mechanical performances. In this research, a detailed investigation was conducted to obtain a superior synthesis of Al–SiC composite materials and to detect the effect of SiC particles distribution on the mechanical characteristic of the stir casted Al matrix composites using glycerol–water based model. The glycerol–water based model study displays the impacts of viscosity of Al melt (1.04–1.24 mPa.s), impeller position (10–50%), stirring speed (100–300 rpm) and blade angle (0–90°) on the vortex height, dispersion time, settling time and clustering of particles. The results of the experiments using glycerol–water based model, 45° blade angles, impeller position of 40% from the base, stirring speed of 250 rpm showed the best uniform distribution of reinforcement particles. Confirmation experiments were carried out by fabricating Al–SiC PRMMC based on three different viscosities (1.04, 1.13, and 1.24 mPa.s) of Al melt and considering other parameters as constant. Fabricated Al–SiC samples were analysed by Scanning Electron Microscope (SEM) and mechanical testing such as tensile, hardness and wear tests. Based on the confirmation results, the viscosity of 1.13 mPa.s for Al melt (at 750 °C) resulted in uniform distribution of SiC particles, which enhanced the tensile strength by 4%, wear resistance by 21%, and led to a uniform hardness value of 47 VHN throughout the composites.