Microstructural analysis of isothermally exposed Ti/SiC metal matrix composites

Specimens of diffusion-bonded titanium metal matrix composites have been subjected to thermal exposure treatments and examined principally by transmission electron microscopy. The fibres investigated were SCS-6 and Sigma. The fibre/matrix reaction layers have been shown to consist of titanium carbide and two titanium silicides. The reaction proceeds by the initial formation of a layer of TiC followed by a layer of mixed silicides, Ti₅Si₄ and Ti₅Si₃. Extensive porosity is generated during the reaction and this prevents the formation of a completely protective interfacial layer.