The melt structures above the liquidus in SiCp/Al composite

The properties and the structures of liquid melt above the liquidus play an important role in determining the resultant properties of the alloy and th e composite. In this paper, the melt structures of SiCp/Al composites with two different reinforcement volume fractions were investigated using liquid metal X-ray diffraction and differential scanning calorimetry. The experim ental results showed that the melt structures of SiCp/Al composite are diff erent from that of liquid matrix alloy, a Si-Si hump in the pair radial dis tribution function in SiCp/Al composite melt and the DSC trace indicated th at Si is not well distributed above the liquidus, the size change of short- range-order (SRO) in SiCp/Al composite melt indicated the diffusion of Si f rom chemical reaction between SIC and molten Al is possible only after a gi ven temperature or after some extent concentration fluctuation of Si. The m echanisms for the observed phenomenon are also discussed in this paper. (C) 1999 Kluwer Academic Publishers.