Protium absorption properties and protide formations of Ti-Cr-V alloys

Ti-Cr-V alloys are known to absorb about 3.8 mass% (H/M=2) of protium (hydrogen atom), but to desorb about 2.4 mass%. This paper aims to clarify protium absorption properties and protide formations of Ti-Cr-V alloys. It was found that higher protium desorption capacity was achieved by increasing Cr content and controlling measurement temperature in order to control the desorption plateau pressure near atmospheric pressure for the alloys with less than 40 at% V content. However, Cr-rich alloys were found to absorb up to H/M =1 because of the formation of the mono-protides. The region with higher protium desorption capacity was obtained. The lattice parameters of the alloys and the enthalpy changes for di-protide formation were estimated from the compositions of the alloys. Moreover, estimated enthalpy changes for di-protide fort-nation and the lattice parameters of the alloys were found to be generally constant on the limited line between appearance of regions of mono- and di-protides. (C) 2002 Elsevier B.V. All rights reserved.