Interfacial reactions in Al/TiC particulate composites produced by pressure infiltration

The reactions between commercially pure aluminium and TiC particulate have been investigated in composites produced by means of pressure infiltration and heat treated at several temperatures in the range 973 - 1273 K. The main reaction products identified in the heat treated composite by means of X-ray diffraction, are alumina and titanium aluminides. The likelihood of possible reactions is investigated by calculating their associated free energies. From this analysis it can be concluded that the direct reaction between aluminium and titanium carbide to produce aluminium carbide and titanium aluminides is favourable only at temperatures lower than 1023 K. Also, several reactions between aluminium and titanium oxides (mainly formed during the heat treatment of the composite) to produce titanium aluminides and alumina, are thermodynamically favourable in the whole temperature range investigated.