Formation of the Structure and Phase Composition of Ti–Al–Ta-Based Materials

The experiments on the preparation of materials based on Ti–3Al–0,5Ta and 3Ti–2Al–Ta systems by self-propagating high-temperature synthesis (SHS) are performed. The influence of the composition of the initial mixture, dispersity of powders, and preliminary mechanical activation on the phase composition and structure of the SHS product are investigated. The optimal ratio of mechanically activated and initial powders in the mixture for the synthesis of materials is determined. The dependence of the structure of final products on the structure of initial powders is established. The use of porous tantalum leads to the formation of the intermetallic matrix based on titanium aluminide with the uniform distribution of Ta particles. It should be noted that tantalum powders of both series under study (which differ by dispersity and morphology) partially reacted already at the stage of mechanical activation with the formation of the Al₂Ta phase. It is shown that aluminum plays the leading role in mechanical activation processes in Ti–Al–Ta reaction mixtures. Indeed, as the amount of aluminum in the reaction mixture decreases, a considerable rise of unreacted tantalum particles in the microstructure of synthesized samples is observed.

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