Porous titanium compacts of fine and coarse sponge titanium powders were re
acted with methane gas to produce Ti-TiC in situ composites. The kinetics o
f titanium carbide formation during the reaction were studied in relation t
o powder size, reaction temperature and time, and methane flow rate. The ti
tanium carbide was initially formed as a layer around each titanium powder
and the rate of formation was found to be diffusion-controlled. Titanium hy
dride was also formed during the reaction but was easily removed by post-va
cuum annealing. A significant reduction of chlorine content in the compact
also resulted during the processing. High temperature vacuum sintering coul
d densify the reacted compacts to over 95% theoretical density and, at the
same time, alter the layered titanium carbide phase into rounded particles.
It was possible to produce fully dense titanium base composites containing
up to 30 vol% by the present gas-solid reaction-based processing, (C) 2001
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