field from the region where the u03b2 and u03bf phases and possibly the u03b1 2 phase coexist in accordance with the first embodiment of the invention thermal treatment of the prepared composite is accomplished by heating the composite to a temperature about 5 to 10 above t sub u03b2 in degrees c for a time about 4 to 25 of the consolidation time the thermal treatment is carried out immediately following the consolidation of the preform prior to cooling the composite and prior to removing the composite from the consolidating apparatus it is important that the time and temperature parameters be chosen such that any additional fiber matrix interfacial reactions are minimized the matrix microstructure of the consolidated conventional alloy composite is a very fine equiaxed alpha structure the result of the large amount of alpha beta deformation during compaction i e superplastic forming diffusion bonding as well as the compaction thermal cycle which is carried out in the alpha beta phase field similarly the matrix microstructures of the consolidated alpha 2 and the consolidated orthorhombic titanium aluminide composites are very fine equiaxed structures heat treatment of these very fine equiaxed structures produces a higher aspect ratio grain structure having increased fatigue crack propagation resistance without significantly increasing the thickness of the fiber matrix reaction zone in accordance with the second embodiment of the invention the alloy fiber preform is consolidated and thermal treatment is carried out by heating the alloy fiber preform to a temperature about 5 to 10 above t sub u03b2 while applying a pressure of at least 10 ksi for a time about 10 to 20 of the 34 normal consolidation time 34 i e the time required for consolidation at a temperature below t sub u03b2 it is important that the time.