Structural and thermodynamic properties of the pseudo-binary TiCr2-xVx compounds with 0.0≤x≤1.2

The TiCr2-xVx compounds with 0.0less than or equal toxless than or equal to1.2 series have been synthesised and characterised by X-ray powder diffraction. X-Ray qualitative and quantitative phase analysis has been carried out on the as-cast alloys using the Rietveld method. The refinements of the structure shows that the materials crystallise either in the hexagonal or in the cubic Laves phase type for low V contents. For x>0.6, the system is found of b.c.c.-type structure only. The pressure-composition-temperature (P-C-T) isotherms measured at 298 K show that the as-cast alloys absorb large amounts of hydrogen, from 4 to 5.2 H/f.u. The P-C-T diagrams reveal also the presence of a relatively flat plateau, and a large hysterisis effect, and correspondingly the hydride cannot be completely dehydrogenated. (C)2002 Elsevier Science B.V. All rights reserved.