In situ observation of fracture in homogeneous and functionally graded 6061Al/SiCp composites

Abstract In the present work, 6061Al/SiCp homogeneous composites and 6061Al/SiCp functionally graded materials were prepared by vacuum hot pressing sintering. Fracture behaviors of composites were studied through three-point bending tests and fracture toughness tests with in situ observation. Results show that SiC content in the composite has a great influence on bending strength and fracture toughness. Bending strength and fracture toughness of functionally graded materials are the results of the strength, plasticity, and interlayer synergy. The fracture mechanism of composites is the initiation and growth of microcracks. A large number of microcracks initiate in matrix of the crack tip region and connect with each other to make the main crack propagate.