Regularities and Mechanism of Formation of Aluminides in the TiH2-ZrH2-Al System

The results of our study of the formation of aluminides in the Ti-Al-Zr system by the hydride cycle (HC) method were presented. The characteristics of aluminides (phase composition, density, and absorption properties) were found to depend on the ratios of titanium and zirconium hydrides and aluminum powders, pressure during compaction of the reaction mixture, and dehydrogenation and sintering modes. A series of single- and double-phase aluminides based on titanium and zirconium were synthesized. Some of the synthesized aluminides reacted with hydrogen without preliminary grinding in the self-propagating high-temperature synthesis (SHS) mode, forming reversible hydrides. The concentration triangle of the Ti-Al-Zr system was constructed. The HC method for the synthesis of aluminides based on titanium and zirconium has significant advantages over the conventional techniques: relatively low temperatures (no more than 1000°C); reaction time ~30–60 min; one-stage formation of single-phase aluminides. The single-phase aluminides Ti0.25Al0.75, Zr0.25Al0.75, Ti0.05Zr02Al0.75, and others were synthesized at temperatures of 650–670°C.