Experimental investigation of fracture toughness in Al 356-SiCp aluminium matrix composite

The developed aluminum matrix composite (AMC) is considered to be a promising material for low and high-temperature applications.Fiber reinforced AMC materials have high specific strength and modules of elasticity, together with excellent heat resistance.This experimental investigation was initiated to study the low-toughness fracture in Al 356-SiCp (silicon carbide particles) with respect to the role of the various elements of the microstructure and their probable contribution.The fracture in this composite is studied experimentally, in terms of fracture toughness testing.The low-toughness fracture is believed to be an inherent property of this composite and is caused mainly by the differential elastic and thermal properties of the two constituents.These differentials degrade the matrix alloy near the interface by its strain hardening capacity and by stress intensification introduced by the SiC particle geometry.Consequently, the matrix near the interface is subjected to high localized damage leading to premature fracture.It is found that the matrix alloy controls both flow properties and fracture in the materials investigated.It is concluded that a higher toughness composite requires a proper choice of constituent properties which dominate the stress state at the interface.