In this thesis, the processing technique of SiC coated carbon fibers reinforced aluminium by using of K_2ZrF_6 as wetting promotion agent is investigated. The effects of heat treatment, silicon alloying of the matrix on the composite properties and the composite interfaces are also studied. It is proved that good precursor wires and fully infiltrated composite can be made by treating of SiC coated carbon fibers with K_2ZrF_6. The tensile strengths of the precursor wires are changed because of the enhanced interfacial bonding strength by heat-treatment. The highest tensile strength of the precursor wires reachs 1450MPa (91% ROM value) after the proper heat-treatment. The interface is stable when heat-treated below 600℃. But the C/Al interfacial reaction is activated and silicon diffuses from interface to matrix at 650℃. It is also proved that alloying the matrix with silicon can suppress the interfacial reaction between SiC coating and aluminium. But the suppression mechanism is different from the classical theory, which is considered to be 'the contribution of statured silicon in the Al-Si-SiC system'. When zirconium exists in this system,. which is chemical affinity with SiC, silicon preferably reacts with zirconium and forms intermetallic (Zr_3Al_4Si_5). Then the surplus silicon constructs the equibilium in Al-Si-SiC system. It is observed that the matrix silicon content of the precursor wires are lowered when the alloy silicon content exceeds 5wt% in the fabrication process. Silicon segregates around the fibers and there is a radius concentration gradient in the matrix of precursor wires. A silicon diffusion model is suggested during precursor wires fabrication process. It is considered that the segregated silicon forms a concentration potenial barrier and prohabits silicon diffusion from melt to the fiber bundle centre, resulting lower silicon content in the matrix. The higher silicon content of alloy also degrades the infiltration property, especially for infiltration of the fiber preforms. TEM study of the composite interfaces shows that the interfacial reaction is very severe for the uncoated fibers. The SiC coating is reacted when the alloy silicon content below 2wt%. No interfacial reaction is found in SiC coated CF/Al-12wt%Si composite. Two kinds of silicon precipitation modes are found near interface, i.e., dotlike precipitation mode of the soluted silicon in the matrix contiguous to interface and silicon crystal precipitation mode on the interface and silicon crystal precipitation mode on the interface. No other form of pure silicon is found in the high silicon contented matrix. Precipitation of (Zr_3Al_4Si_5) intermetallic at interface is also found in SiC coated CF/Al-12wt%Si composite. In the matrix, zirconium exists in the form of Al_3Zr in the CF/pure Al and CF/Al-12wt%Si composites, while it changes to the form of (Zr_3Al_4Si_5) when more silicon is added into matrix.
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