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A magnetron sputtering equipment for fibre coating with matrix and metal matrix composite (MMC) processing is described. For the matrix deposition two pairs of magnetrons are used. The fibres are wound on a cylindrical fibre holder, which rotates round the cylinder axis during matrix deposition. The chemical concentration of the alloying elements in the coating is in good agreement with that of the target material and the oxygen pollution in the coating can in most cases be suppressed to a level lower than 1500 ppm. The depositon of γ-TiAl with 2% Cr and 2% Nb from targets made of pure metals is discussed.

The microstructure of the Ti-6Al-4V matrix in SiC-fibre reinforced composites is characterised using light microscopy and is correlated to the composite processing parameters. The microstructures are compared with those of thermally and thermomechanically treated Ti-6Al-4V specimens

The thermal stability of the interface in an SiC-fiber reinforced Ti6Al4V-alloy was investigated using analytical transmission electron microscopy. Composites processed by hiping were heat-treated in vacuum between 600 °C and 800 °C for several hundred hours. The structure of the interface was investigated by TEM, and the element concentration in and near the interface was measured using EDX-STEM and EELS. Experimental errors resulting from the sample preparation are discussed. Based on the structural and analytical investigations, the conclusion can be drawn that the interface is stable for application temperatures of up to about 600 °C.

One of the major future applications of titanium matrix composites is as a material for airplane turbine components, e.g., in the compressor. Service temperatures of up to 800 C will be involved. This application objective will only be reached when it will be possible to solve two major material problems: first, a matrix with sufficient ductility at room temperature and sufficient strength at service temperatures has to be found; and second, the problem of fiber/matrix reaction at application temperatures has to be solved. In composites with the high ductility IMI834 alloy (Ti-5.8Al-4.0Sn-3.5Zr-0.7Nb-0.5Mo-0.35Si-0.06C in wt. pct) as matrix, the optimal tensile properties can be exploited: the ultimate tensile strength and Young`s modulus values are in accordance with the prediction of the rule of mixtures, and an elongation at fracture of nearly 1.3 pct, typical of SiC fibers, is measured. It was shown that in SiC-SCS-6 fiber-reinforced IMI834 composites, these properties are achieved up to temperatures of 1,000 C. In the present study, results of the thermal stability of the SiC-SCS-6 fiber-reinforced IMI834 alloys are presented.

Description d'une technique analytique pour identifier et quantifier l'azote dans les aciers allies. Utilisation de la spectrometrie Auger