A plasma spray process for the manufacture of long-fiber reinforced Ti-6Al-4V composite monotapes

A fabrication method for titanium matrix composite monotapes reinforced by long SiC fibers is described. The plasma spray technique, carried out in an inert atmosphere, was used to deposit the metal matrix onto previously arranged continuous fibers. Major benefits are due to a controlled operating environment (the entire process is performed in a neutral gas atmosphere) and to the high solidification rate of the melted material. The formation of deleterious brittle reaction products between the fiber and matrix is therefore limited. Plasma spraying, normally used as a coating technique, was modified to produce a long composite monotape. This required a suitable arrangement of the fiber, placed onto a cylindrical substrate, and the identification of suitable operating conditions, as described in the present work. The results of characterization tests performed on the tape, with special reference to the quality of the fiber/matrix interface, are summarized. Results of preliminary diffusion bonding experiments carried out by means of a hot pressing system are also reported.