Publication Date:
2011-03-03
Description:
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.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
