Reactions in Al-10 wt.% TiC metal matrix composites have been investigated
by heating samples between 600 and 900 degreesC for 48 h and holding at 700
degreesC for periods up to 240 h. X-ray diffraction, scanning electron mic
roscopy and image analysis have been used to identify the composition, morp
hology and quantities of the reaction phases present. A maximum reaction ra
te was observed at 700 degreesC and at this temperature the reaction produc
ts formed were large Al3Ti precipitates in the bulk of the matrix and Al4C3
blocks at the particle-matrix interface. At 900 degreesC, TiC appeared to
be stable in Al. The reaction kinetics for TiC followed a parabolic rate in
dicating a diffusion-controlled process. The rate of TiC dissolution is ver
y much less than that for SiC in pure Al. (C) 2001 Elsevier Science B.V. Al
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