WETTING BEHAVIOR AND MULLITE FORMATION AT THE INTERFACE OF INVISCID MELT-SPUN CAO-AL2O3 FIBER-REINFORCED AL-SI ALLOY-(4032) COMPOSITE

Inviscid melt-spun calcia-alumina fibre-reinforced aluminium-silicon a lloy (4032) composites were produced using a melt-infiltration techniq ue. Scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to investigate interfaci al wetting and interphase formation, and identify the crystalline phas e of the interphase of these composites. The composites processed at 7 00 degrees C showed a good interfacial wetting and silicon accumulatio n at the interface. The composites processed at 927 degrees C showed f ormation of an interphase region of about 10-20 mu m thick, as well as excellent interfacial wetting. EDS analysis gave averaged composition s of this interphase region at 74 wt % Al and 26 wt % Si, which corres ponds to the composition of mullite (3Al(2)O(3).2SiO(2)). The formatio n of mullite at the interface was confirmed by XRD analysis.