Microstructure and Mechanical Behavior of Magnesium Alloy Az91 Hybrid Composites

Abstract

AZ91 magnesium alloy hybrid composites reinforced with various ratios of SiC and graphite particles were synthesized by stir casting. The composites were prepared by varying the weight percentage of SiC and graphite particles each from 0 to 3 in steps of 1 weight percent. The average particle size of both the reinforcement particles was 27?m. The effect of reinforcement is discussed for both heat treated and non-heat treated composites and compared with unreinforced base alloy. The microstructure reveals that there is a nearly uniform dispersion of particles is the matrix. The density, hardness and ultimate tensile strength of the composite specimen increased as the percentage of reinforcement was increased both in heat treated and non-heat treated conditions. The percentage of elongation decreases as the reinforcement in the composites increased. SEM micrographs of the tensile fracture surfaces showed broken reinforcement particles on the fracture surface and evidence of 'pull outs', where graphite/SiC particles were previously embedded in the matrix. © Published under licence by IOP Publishing Ltd.