Hydrogen absorption properties of Ti-Cr-A (A=V, Mo or other transition metal) bcc solid solution alloys

The pressure-composition isotherms (P-C-T) for hydriding of Ti-Cr binary alloys and Ti-Cr-A (A=V, Mo or other transition metal) ternary alloys with bcc structures were measured to examine the effect of the composition on the hydrogen-absorbing capacity and equilibrium dissociation pressure. In the Ti-Cr binary system two plateau regions were recognized in the P-C-T curves as in other bcc-type alloys. The Ti-Cr alloy with 33at.% Ti (Ti sub 33 Cr sub 67 ) shows the best P-C-T characteristics in the Ti-Cr binary system, although the maximum hydriding capacity is lower than in alloys with a large Ti content. The maximum absorbing capacity was increased by the addition of V or Mo to the Ti sub 33 Cr sub 67 bcc alloy. After 1000 absorption-desorption cycles the hydriding capacity of the TiCrV (Ti sub 33 Cr sub 33 V sub 33 ) bcc alloy decreased to 70% of the initial capacity. The TiCrV bcc solid solution alloy has excellent resistance to pulverization compared with intermetallic compounds.