EXPERIMENTAL APPROACHES TO SIMULATING INTERFACIAL REACTIONS IN METAL-MATRIX COMPOSITES

Samples of a titanium aluminide have been subjected to treatments desi gned to simulate their contact with the protective layer of a commerci al silicon carbide fiber; such contact occurs during fabrication of ac tual metal matrix composites (MMCs), The first treatment consisted of immersion of the matrix material in a powder mixture, the composition of which corresponded to that of the protective layer of the fiber. Th e second method was the chemical vapor deposition (CVD) of such a laye r. Subsequent isothermal exposure treatments showed that these methods produced interfacial reaction layers which very closely resembled the layers present in actual composites. It is concluded that approaches such as these are viable methods for evaluating the efficiency of pote ntial coatings or surface modifications without the necessity of perfo rming full-scale composite fabrication tests.