Ti 3Al destructive hydrogenation

Abstract

In the present paper it was determined, that interaction between α 2-Ti 3Al alloy and hydrogen in temperature range between 298 and 1533 K is performed in accordance with the reaction of the destructive hydrogenation and its products are titanium hydrides and intermetallic compounds Al-enriched in comparison with Ti 3Al. The structurally-phasemechanism of α 2-Ti 3Al destructive hydrogenation consists in the following. From the beginning solution of hydrogen in Ti 3Al leads to disordering of its crystalline structure. Then hydrogen interacts not with the disordered alloy, but with titanium, which goes out from Ti 3Al, accordingly to the scheme: TiH 2(bct) → TiH 1,9(fcc) → β-Ti-H y (bcc) → α-Ti-H x (hexagonal) → α-Ti (hexagonal). The intermetallic compounds with the enhanced aluminum content are arised, when suitable stoichiometric concentrations are formed. The monolithic composites with nano-size components were obtained by means of Ti 3Al destructive hydrogenation at 973 K during 1 and 4 h. Their phase compositions were Ti 3Al-(α-TiH–Ti 3− x Al) and ((α-Ti-H x )–(β-Ti-H y )–TiH 1,9(fcc)–TiH 2(bct))–(Ti 3Al–TiAl–TiAl 2) correspondingly. These composites consist of continuous matrixes and inclusions situated in them.