Numerical analysis of the effect of microstructures of particle-reinforced metallic materials on the crack growth and fracture resistance

This paper presents a systematical computational study of the effect of microstructures of materials reinforced with brittle hard particles on their fracture behavior and toughness. Crack growth in particle-reinforced materials (here, in high speed steels) with various artificially designed arrangements of brittle inclusions is simulated using microstructure-based finite element meshes and an element elimination method. The following types of brittle inclusions arrangements are considered: (simple microstructures) net-like continuous, band-like, random with different inclusion sizes, and (complex microstructures) layered and clustered arrangements, with different inclusion sizes and orientations. Crack paths, force-displacement curves, fracture toughness and fractal dimension of fracture surfaces are determined numerically for each microstructure of the materials. It is demonstrated that extensive crack deviations from the initial cracking directions and an increase in the fracture toughness can most efficiently be achieved by using complex microstructures, such as alternated layers of fine and coarse inclusions.