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The manuscript presents a close examination of the titanium and aluminum platters manufactured by explosive welding method. In particular, the microstructure changes of the Al/Ti wavy shape interface after annealing at 773 and 903 K were studied. Three stable TiAl 3 , TiAl, and Ti 3 Al and a metastable TiAl 2 intermetallic phases have been formed in the state directly after explosive welding. The orientation map and TEM images obtained after explosive welding process showed very fine grains of aluminum mixed with intermetallics in the interface region between the peninsulas or islands. After annealing for 100 h the TiAl 3 continuous layer was obtained; however, the layer achieved at 903 K was much wider than that obtained at 773 K. An examination of the growth kinetics at 903 K revealed that incubation time was less than 5 min. After this period, the growth was solely governed by chemical reaction.

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The microstructure and phase composition of Al/Ti/Al interfaces with respect to their localization were investigated. An aluminum-flyer plate exhibited finer grains located close to the upper interface than those present within the aluminum-base plate. The same tendency, but with a higher number of twins, was observed for titanium. Good quality bonding with a wavy shape and four intermetallic phases, namely, TiAl 3 , TiAl, TiAl 2 , and Ti 3 Al, was only obtained at the interface closer to the explosive material. The other interface was planar with three intermetallic compounds, excluding the metastable TiAl 2 phase. As a result of a 100-hour annealing at 903 K (630°C), an Al/TiAl 3 /Ti/TiAl 3 /Al sandwich was manufactured, formed with single crystalline Al layers. A substantial difference between the intermetallic layer thicknesses was measured, with 235.3 and 167.4 lm obtained for the layers corresponding to the upper and lower interfaces, respectively. An examination by transmission electron microscopy of a thin foil taken from the interface area after a 1-hour annealing at 825 K (552°C) showed a mixture of randomly located TiAl 3 grains within the aluminum. Finally, the hardness results were correlated with the microstructural changes across the samples.

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