Interfacial reaction and its influence on the mechanical properties of theASZ short fibre-reinforced Al alloy composite

The effect of interfacial reaction on the mechanical properties of the AC8A Al alloy reinforced with ASZ short fibres (ASZ/AC8A composite) was studied . In the ASZ/AC8A composite, the interfacial reaction was observed to proce ed between the SiO2 binder layer and Mg of the matrix td form MgAl2O4 at th e interface. Formation of MgAl2O4 was believed to enhance the interfacial b onding strength, resulting in the improved composite strength. However, the interfacial reaction in the ASZ/AC8A composite always took place at the ex pense of Mg in the matrix, resulting in the composite devoid of the Mg bear ing precipitates such as Al2CuMg and Mg2Si. Interfacial reaction mechanisms were investigated for composites containing various Mg contents. The resul tant mechanical properties of the composite were measured to determine the adequate amount of Mg within the composite. Microstructural changes of the composite were observed using transmission electron microscopy and differen tial scanning calorimetry to provide qualitative analyses on the experiment al observations.