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The paper examines how the structure and phase composition of Ti-Al-B alloys evolve at various consolidation stages in the composite powder mechanochemical synthesis and subsequent sintering under pressure. Two powder alloys with different boron content are studied. The amount of aluminum in both initial powder mixtures is the same and corresponds to TiAl. The content of boron is selected so as to form an aluminide matrix with 10 and 25 vol.% borides. It is established that phases form in the mechanochemical synthesis in the following sequence: Ti + Al → Ti (Al) → TiAl 3 and Ti 3 Al → TiAl. Titanium borides are formed simultaneously with TiO 2 and TiAl or after them, which confirms that these processes are interrelated. The mechanochemical synthesis for hours in a planetary-ball mill results in the formation of micron particles that have agglomerated or conglomerated (sometimes layered) composite structures. X-ray analysis is used to study the phase evolution of Ti-Al-and Ti-Al-B alloys. It is shown that the presence of boron in mechanical alloying reduces the degree of amorphization and promotes the formation of fine crystalline structure. In addition, the presence of boron prevents the formation of metal oxides and a number of intermetallides. It is established that the sintered dispersion-hardened Ti-Al-B material consists of an aluminide matrix with micron and submicron inclusions of borides. The increase in boron content leads to a higher amount of boride inclusions. As a result, the distance between them decreases and thus microhardness increases.

621.793We have studied phase formation in detonation coatings sprayed from Ti − 50 at.% Al powders. The powders of the alloy were obtained by various methods: crushing an ingot and mechanical alloying of Ti and Al. Using polyphase nanostructural materials activated by mechanical alloying makes the process of phase formation in the gas-thermal sprayed coatings based on them more general-purpose and controlled due to the more active and more subtle reaction of the material with the gaseous atmosphere.We have shown that from mechanically alloyed Ti − 50 at.% Al powder, using the detonation-gas spraying method we can consolidate a coating based on Al 2 TiO 5 by oxidizing action of the working gas on the powder and also a coating based on titanium aluminides with TiN inclusions by nitriding action.The phase composition of the cast microstructural γ-TiAl powder is inherited by the coating.