This article describes the effect of squeezing process on the porosity of partially remelted A319/20 vol.-% SiC particulate reinforced metal matrix composites (MMCs). The composite alloy was originally fabricated by stir casting technique. The effect of squeezing process parameters such as the squeezing time, compressive stress and the liquid weight fraction inside the melt on the overall porosity was extensively studied. It was found that the squeezed composites have lower overall porosity when compared to the as-cast composites. The lowest overall porosity content was observed when the squeezing process parameters are at their peak values. After squeezing, the gas bubbles voids were practically eliminated. While the inter-particles voids were significantly reduced but not completely eliminated due to fracture of SiC particles and generation of new inter-particles micro-voids. Pin-on-disc wear tests were conducted to evaluate the effect of porosity of the wear resistance of the composites. An artificial neural network (ANN) modelling for wear behaviour of the composite alloy has been established. The developed model takes into account the effect of porosity on the wear resistance of MMCs. The results showed that, the wear resistance of the squeezed composites is significantly higher than the as-cast composites due to the lower porosity content of the squeezed composites. |
