The influence of particles size and its distribution on the degree of stress concentration in particulate reinforced metal matrix composites

In this work, the degree of stress concentration in particulate reinforced metal matrix composites (PRMMCs) is investigated by finite element analysis method. It is found that, besides the particle morphology, particle size and its distribution can also remarkably influence the stress distribution of the composites, especially that in the matrix. The results indicate that the particles will bear more loads in the composites reinforced by irregular particles than those reinforced by spherical ones and the stress concentration in the matrix near the particle angularity is more serious. As to the particle size, the degree of stress concentration in the matrix will be reduced with the decrease of the size, while the size distribution has greater influence on that than the size itself. The calculated standard deviation of the stress indicates that the degree of stress concentration in matrix in multi-size particles reinforced models is obviously weaker than that in single-size particles reinforced models. Therefore, changing the size distribution is more effective to reduce the degree of stress concentration in the matrix and can be used to improve the fracture toughness of PRMMCs. It is considered that the results could be helpful for design better performance PRMMCs by controlling the ratio of particles with different sizes.