Experimental observation and numerical simulation of SiC3D/Al interpenetrating phase composite material subjected to a three-point bending load

The failure process and the underlying mechanism of crack initiation, crack propagation and eventual fracture of SiC3D/Al interpenetrating phase composite subjected to a static three-point bending load were investigated using in-situ SEM observation and two-dimensional microstructure-embedded numerical simulation. It was found that stress concentration originally occurred in the SiC ceramic phase near the bottom of the specimen, causing horizontal tensile forces and inducing a vertical microcrack inside the SiC phase near the SiC–Al interface. With increased load, more microcracks were gradually initiated in the SiC phase, and severe tearing plastic deformation and cracking of the Al phase occurred at the base of the specimen. Subsequently, the microcracks propagated and connected to form a primary crack. It was notable that at the final stage of the primary crack, cracking in the Al phase no longer occurred due to the sudden release of the internal energy in the composite material. Interestingly, the primary crack bridged over the Al phase then continued to propagate in the SiC material. Simulated results were consistent with observed behavior.