Functionally gradient metal matrix composites: Numerical analysis of the microstructure–strength relationships

The effect of microstructures of graded SiC particle reinforced Al matrix composite on their mechanical behavior, strength and damage resistance was investigated on the basis of the computational testing of different artificially designed graded microstructures of the composites. The tensile stress–strain curves, fraction of failed particles, and stress, strain and damage distributions at different stages of loading were determined for different gradient microstructures of the composites, with varied particle arrangements, shapes, sizes and orientations. It was shown that flow stress and stiffness of composites decrease, and failure strain increases with increasing the degree of gradient of the particle arrangement. The orientations of particles have a strong impact on failure strain and damage growth in the composites reinforced with the elongated or plate-like particles: whereas the horizontally aligned particles ensure the highest failure strain, the vertically aligned particles lead to the lowest and the randomly oriented particles to the medium failure strain. The damage growth in the SiC particles in gradient composites begins in the particles, which are located in the transition zone between the zone of high particle density and the particle-free regions.