Processing of continuously reinforced Ti-alloy metal matrix composites (MMC) by magnetron sputtering

The present work deals with a novel vapor synthesis route, the matrix-coated fiber process, for producing SiC fiber reinforced Ti–6Al–4V and Ti3Al–Nb ‘orthorhombic’ titanium aluminide composites. In this process, the matrix alloys were directly deposited on SiC fibers by magnetron sputtering. The matrix deposition was conducted both as a batch process, wherein short-length fibers were coated with the matrix material using a planar magnetron sputtering system, as well as a continuous process, in which the matrix was deposited on continuous SiC fibers using a reel-to-reel hollow-cathode magnetron sputtering system. The matrix-coated fibers were consolidated to produce unidirectionally reinforced composite panels. Unreinforced matrix alloy samples were also fabricated using the same sputtering and consolidation conditions. Following heat treatments, the microstructural evolution in these materials were studied. Tensile tests at room temperature were also conducted on matrix and composite specimens. The results indicated that PVD foils and fiber coatings can be heat-treated to obtain microstructures similar to those obtained via conventional processing approaches. Further, the room-temperature tensile properties of PVD foils are comparable to conventionally rolled foils or sheets.