Development of 2014-Al Alloy Based SiCp Particulate Reinforced Composites by Spray Co-deposition Process

Abstract

Aluminium based metal matrix composites containing SiCp particulates were produced by spray co-deposition process. The mass median diameter and mass flow rate of SiCp were varied from 6 to 58 m and from 10 to 30 mass% of the melt flow respectively. Porosity and SiCp content were measured at different positions in the preform. The mass fraction of reinforcement incorporated in the preform varies from 4 to 17%, which is caused by low compaction efficiency of secondary particulates. Porosity is observed to increase with increase in the surface area of the reinforcement. Optical microscopy shows an uniform distribution of particles. However, smaller size particles are pushed towards the grain boundaries during solidification in contrast to large size particles. The grain size of the matrix decreases with increase in the SiCp content. The matrix grain size varies from 15 to 50 m. This effect of decreasing grain size is more sensitive to small size particulates. Optical microscopy and SEM analysis of overspray powder particles show that the collision of melt droplets and SiCp particles to be the major mechanism for incorporation of small particles in particular.