Evaluation and optimization of metal matrix composite strip produced by single roll continuous strip casting method

Abstract

Metal matrix composite (MMC) strip has been made in single step through ingot metallurgy route using single roll continuous strip casting (SRCSC) technology. Composite melt of Al-Si alloy matrix and SiC particulate was prepared through vortex disperion method. Wetting characteristics of particles were improved by alloying with magnesium, preheating of particles at high temperature and stirring of composite melt. Process parameters of composite melt preparation and strip casting were optimized and composite strips were produced with different sizes of reinforcing particle and with different wt.% of particle. Particle recovery and distribution, quality of composite strip and mechanical properties at room temperature as well as at high temperature were studied w.r.t. size of particle, amount of particle added to the matrix and rotational speed of caster drum. It has been observed that size and distribution of reinforcing particle in the matrix affects the mechanical properties. Smaller size particles improve the strength and hardness of the composite. But in case of coarse particles (53-75 mu m), distribution and recovery is found to be better than that of smaller size particles (<25 mu m). Better distribution of particles and increase in strength was also observed at higher rpm of the caster drum. Composite strips have shown better strength at elevated temperature (<250 degrees C) than the matrix alloy. Improvement in ductility of composites was also noted at elevated temperature. (C) 2007 Published by Elsevier BN.