Microstructural and Phase Composition Differences Across the Interfaces in Al/Ti/Al Explosively Welded Clads

The microstructure and phase composition of Al/Ti/Al interfaces with respect to theirlocalization were investigated. An aluminum-flyer plate exhibited finer grains located close tothe upper interface than those present within the aluminum-base plate. The same tendency, butwith a higher number of twins, was observed for titanium. Good quality bonding with a wavyshape and four intermetallic phases, namely, TiAl3, TiAl, TiAl2, and Ti3Al, was only obtained atthe interface closer to the explosive material. The other interface was planar with threeintermetallic compounds, excluding the metastable TiAl2 phase. As a result of a 100-hourannealing at 903 K (630 C), an Al/TiAl3/Ti/TiAl3/Al sandwich was manufactured, formed withsingle crystalline Al layers. A substantial difference between the intermetallic layer thicknesseswas measured, with 235.3 and 167.4 lm obtained for the layers corresponding to the upper andlower interfaces, respectively. An examination by transmission electron microscopy of a thin foiltaken from the interface area after a 1-hour annealing at 825 K (552 C) showed a mixture ofrandomly located TiAl3 grains within the aluminum. Finally, the hardness results werecorrelated with the microstructural changes across the samples