Effect of particle shape in the Young moduli of SiC particle reinforced Al matrix composite
Particulate reinfoced metal matrix composites (PRMMC) show good combination of strength-to-weight ratio, as a result they are used commonly in fields such as the automotive, aerospace, electronics, among others. Tipical PRMMC are made of metal matrixes such as aluminium and magnesum, whereas reinforcement particles are silicon carbide, alumine, among others. Particle reinforments exhibit angular and circular shapes. Young moduli of PRMMC depend strongly on factors such as the volume fraction reinforcement, particle shape, particle size as well as particle orientation and cohesive forces at the particle-matrix. The experimental development of PRMMC is time consuming and cost effective. For desing purpose analytical models have been development, however, they exhibit a different degree of reability depending on the Young modulus strength ratio for example, hence they are limited to certain applications. In recent decades the finite element analysis (FEA) of microstructures have shown to be an accurate approach to determine the elastic modulus of PRMMC as function of particle shape, particle size, particle volume fraction, etc. In this work a micromechanical model was developed and solved using COMSOL Multiphysics. The Solid Mechanics module is used for the stationary study of two-dimensional microstructures, where the effects of particle shape, particle volume fraction and particle size on the elastic modulus. The MMC studied is a silicon carbide particle reinforced aluminium-based matrix composite. The finite element outcome are validated by comparing the numerical predictions against several experimental data ranging in low and high-volume fraction and good agreement is found. The elastic modulus of aluminium reinforced silicon carbide increases as volume fraction reinforcement increases. The smaller cicular paricles considered in the study act as stress concentrator, whereas, stress is concentrated in sharped corners of angular particles. The elastic modulus is sensitive to the particle morphology, where angular particles exhibit better stregthening effect for a given volume fraction when compared to cicular particles.
