Hydrogen absorption and desorption in Ti−Al alloys

Abstract

Binary Ti_1−xAl_x and ternary Ti_0.75−xAl_0.25M_x (M=V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Pd, Hf, Ta and W; x=0.15 and 0.25) alloys reacted slowly with 5.0 MPa H₂ at room temperature for different periods. The hydrogen absorption capacity, the 50% hydrogen desorption temperature (T _d) and the structures of their hydride were investigated. Amorphous and fcc type hydrides formed by hydrogenation of the binary Ti−Al alloys. As the Al concentration increased in the Ti−Al alloys, the hydrogen absorption capacity decreased, while the hydrogen desorption temperature decreased at once and then increased again. Amorphous, fcc, bcc and C14 Laves type hydrides formed by hydrogenation of the ternary Ti₃Al− based alloys. The hydrogen absorption capacity was reduced despite whatever elements were substituted for Ti in Ti₃Al. Ni, Co, Mn and Nb have the ability to reduceT _d of Ti_0.75−xAl_0.25M_x.