Commercially pure aluminum and commercially pure titanium plates have been explosively welded and annealed at temperature of 630 °C for 5, 20, 50 and 100 hours. The investigation of intermetallic formed during explosion welding and heat treatment processes has been carried out. The metallographic studies showed variation in the intermetallic volume fraction according to the deformation degree of different interfaces. Moreover the relation between the intermetallic layer thickness and time of explosively welded “Al-Ti” composite annealing has been found. The X-ray analysis reviled that intermetallic layer formed during the heat treatment process consisted of Al3Ti compound.