Tensile, fracture toughness and fatigue crack growth rate properties of silicon carbide whisker and particulate reinforced aluminum metal matrix composites

Abstract Silicon carbide whisker or particulate reinforced aluminum metal matrix composites, especially attractive because of their superior strength, stiffness, low cycle fatigue properties, corrosion fatigue behavior, creep resistance and wear resistance compared with the corresponding wrought aluminum alloys, have shown promise for various critical structural applications. The major drawback of these materials, however, is their less than ideal ductility, fracture toughness and fatigue crack growth rate (FCGR) properties. Consequently, in order to develop a succinct, structural reliability prediction capability that could be easily applied by design engineers to structures manufactured from these metal matrix composites and to examine initial methods whereby the ductility, fracture toughness and crack growth resistance of these materials might be improved, room temperature tensile, fracture toughness and FCGR tests were conducted on 20 v/o SiCw/2124Al (T6), 25 v/o SiCp/6061 Al (F and T6) and 25 v/o SiCw/6061 Al (T6) metal matrix composites. Compared with the corresponding wrought aluminum alloys, the three subject metal matrix composites demonstrated increased yield and ultimate strengths, substantially inferior ductility and fracture toughness, a lower crack propagation resistance and essentially equivalent values of threshold stress intensity range, Δ K th .