Role of segregation and precipitates on interfacial strengthening mechanisms in SiC reinforced aluminium alloy when subjected to thermomechanical processing

The satisfactory performance of metal matrix composites depends critically on their integrity, the heart of which is the quality of the matrix-reinforcement interface. The nature of the interface depends in turn on the processing of the metal matrix composite component. At the micro-level the development of local concentration gradients around the reinforcement, as the metal matrix attempts to deform during processing, can be very different to the nominal conditions and play a crucial role in important microstructural events such as segregation and precipitation at the matrix-reinforcement interface. These events dominate the cohesive strength and subsequent mechanical properties of the interface. The compositional variations at the matrix-reinforcement interface of a metal matrix composite are reported, emphasising the interfacial strengthening mechanisms during thermomechanical processing. A method of calculation has been applied to predict the interfacial fracture strength of aluminium and SiC interface, in the presence of magnesium segregation.