Microstructure and storage properties of low V-containing Ti–Cr–V hydrogen storage alloys prepared by arc melting and suction casting

The microstructure and hydrogen storage properties of low V content (Ti_(0.46)Cr_(0.54))_(100?x) V_x (x = 2.5–7.1, at%) and (Ti_y Cr_(1?y))_(95)V_5 (y = 0.38–0.54) alloys were investigated. These alloys were prepared by arc melting and copper mould suction casting. The structures of as-cast (Ti_(0.46)Cr_(0.54))_(100?x) V_x (x = 2.5, 5.0, and 7.1) alloy ingots evolve with V contents from pure Laves- (x = 2.5) to dual-phase TiCr2-BCC structures (5.0 and 7.1), whereas the suction-cast (Ti_(0.46)Cr_(0.54))_(100?x) V_x (x = 2.5, 5.0, and 7.1) alloys only contain single BCC phase. The suction-cast alloy rod (Ti_(0.46)Cr_(0.54))_(95)V_5, containing only 5.0 at% V is shown to possess the optimum hydrogen absorption capacity, with the maximum hydrogen content of 3.14 wt%. Furthermore, the hydrogen storage properties of the suction-cast low V alloys (Ti_y Cr_(1?y))_(95)V)5 (y = 0.38–0.54) are sensitive to Ti/Cr ratios and only those alloys with Ti/Cr ratios close to the CN14 cluster Ti_7Cr_8 have good hydrogen storage properties