Strengthening and fracture behaviors in SiCp/Al composites with network particle distribution architecture

Recent experimental works proved that metal-matrix composites (MMCs) with quasi-continuous network architecture presented higher stiffness and strength than homogeneous composites. Here a three-dimensional (3D) model with network particle architecture was established and the strengthening and fracture behaviors were numerically investigated. The results show that SiC particle walls parallel to the external load direction have higher load-carrying capacity, while the walls perpendicular to load direction exhibit similar stress with homogeneous composites. So the strengthening effect of network architecture is attributed to the high load-bearing capacity of concentrated SiC particle walls rather than dispersed particles. In network composites, particle fracture in SiC walls parallel to the load direction results in the crack initiation by interfacial decohesion at small load (ε_xx = 1.0%) and SiC particle fracture at higher load (ε_xx = 2.0%). Large matrix phase can blunt and deflect cracks, and thus reduce the crack propagation rate. On the other hand, particle fracture initially occurs on SiC walls perpendicular to the load direction. The main crack propagates rapidly through the network boundary.