The Reactivity of Ti2AlC and Ti3SiC2 with SiC Fibers and Powders up to Temperatures of 1550°C
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The reactivities of commercially available Ti 2 AlC or Ti 3 SiC 2 powders with uncoated SiC fibers or SiC powders were evaluated in this paper. When Ti 2 AlC-SiC samples were hot pressed or hot isostatically pressed at temperatures up to 1500°C, fully dense composites were obtained. The latter were characterized by X-ray diffraction and electron-dispersive spectroscopy in a scanning and transmission electron microscope. Differential thermal analysis up to 1550°C was also carried out. In all cases, SiC reacted with the Ti 2 AlC powder resulting in the formation of Ti 3 (Al 1-x Si x )C 2 TiC and Al 1+x Ti 1-x , where x ranges from 0 to 1. In the limit x=1, pure Al forms. Conversely, Ti 3 SiC 2 samples, reinforced with uncoated SiC fibers or powders, can be hot pressed in vacuum at temperatures as high as 1500°C to produce fully dense composites with no apparent reaction between the matrix and fibers. Based on these results, Ti 3 SiC 2 can, but Ti 2 AlC cannot, be reinforced with SiC. Such reinforcements will be needed if the MAX phases are to be used as structural materials at very high temperatures. © 2011 The American Ceramic Society.
author list (cited authors)
Spencer, C. B., Córdoba, J. M., Obando, N. H., Radovic, M., Odén, M., Hultman, L., & Barsoum, M. W.