Metal matrix composites attracted a lot of attention due to their special properties such as high fatigue resistance, good dimensional stability and great strength to weight ratio. Titanium aluminides are used in space and automobile industries because of great features such as low density and good corrosion resistance at high temperatures. Titanium aluminides can be produced by reaction between titanium particles and aluminum matrix. For this purpose, two accumulative roll bonding (ARB) and annealing process have been used. At first, Ti particles (with average size of 48 µ) have been dispersed through Al foils by ARB and then these Ti particles changes into TiAl 3 during an in-situ reaction . Applying more rolling cycles creates a uniform distribution of particles in the matrix and a strong mechanical bond at the interface that results in mechanical activation in this area (interface). Moreover, post-rolling annealing cause thermal activation in reaction between Ti particles and Al matrix, so that facilitates TiAl 3 formation. Therefore distribution of particles, morphology, microsctructure and interface of reinforcements have been studied by optical microscope, x-ray diffraction, scanning electron microscope, field-emission scanning electron microscope and electron probe micro analysis. Al-TiAl 3 composite formed by 20 rolling cycles and annealing after 5 and 9 cycles (2 hours at 430?C) and 12, 17 and 20 cycles (2 hours at 600 ?C) showed the most amount of TiAl 3. Particles with size of 200 nm have been also observed in this composite. The area covered by particles reached to 22%. Microhardness of this composite increased from 25 vickers (hardness of annealed aluminum foil) to 59 vickers.
