Inviscid melt-spun calcia-alumina fibre-reinforced aluminium-silicon alloy (4032) composites were produced using a melt-infiltration technique. Scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to investigate interfacial wetting and interphase formation, and identify the crystalline phase of the interphase of these composites. The composites processed at 700 degrees C showed a good interfacial wetting and silicon accumulation at the interface. The composites processed at 927 degrees C showed formation of an interphase region of about 10-20 mu m thick, as well as excellent interfacial wetting. EDS analysis gave averaged compositions of this interphase region at 74 wt % Al and 26 wt % Si, which corresponds to the composition of mullite (3Al(2)O(3).2SiO(2)). The formation of mullite at the interface was confirmed by XRD analysis.