Micromechanical fracture process of SiC-particle-reinforced aluminium alloy 6061-T6 metal matrix composites

To investigate the role of microstructural parameters on the fracture mechanism, SiC-particle-reinforced aluminium alloy 6061-T6 composites with 5, 10, 20 and 30% volume fraction were tested to measure the fracture toughness on a precracked compact tension specimen. The interparticle spacing of two adjacent particles with the critical size was related to the fracture toughness. The critical particle diameter was experimentally determined from the plastic zone size and the crack-tip-opening displacement using the Hutchinson-Rice-Rosengren solution and the Hahn-Rosenfield model. It has been found that the critical particle diameter decreased as the volume fraction of SiC particles increased.