Severe plastic deformation and hydrogenation of the titanium aluminides

Abstract

Severe plastic deformation (mechanical activation in a hydrogen atmosphere and shear under pressure) effects on the hydrogenation of two titanium aluminides Ti 3Al and TiAl-type alloy (B2) have been studied. It is shown that a conventional hydrogenation of the bulk samples allows forming the hydrides with high hydrogen content and high desorption temperature: TiAl (773 K, 1.76 mass%) and Ti 3Al (1043 K, 2.94 mass%). In comparison with the conventional hydrogenation, the mechanical activation in a hydrogen atmosphere at room temperature allows one to obtain the hydrides of the TiAl (B2) and Ti 3Al alloys with the reduced desorption temperature: TiAl (453 K, 1.96 mass%) and Ti 3Al (531 K, 2.6 mass%). The shear under pressure has been applied to the sample before hydrogenation also leads to a reduction of the desorption temperature; however, it produces the phase transformation in the Ti 3Al intermetallic compounds, which lowers the observed a maximum hydrogen content.