Effect of hypo-stoichiometry on microstructure and hydrogenation behaviors of multiphase ZrTi0.1V2-x alloys. (March 2022)

• Record Type: Journal Article
• Authors: Zhang, Yunlong; Li, Ruolin; Cong, Mengqi; Chen, Yi; Cheng, Liang; Zhu, Bin; Xie, Lishuai
• Is Part Of: Intermetallics. Volume 142(2022)
• Publication Date: 2022-03
• Subjects: Hydrogen absorption -- Laves phase -- BCC -- Stoichiometry; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2022.107464
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: ZrTi0.1 V2- x ( x = 0, 0.2, 0.4) alloys are designed to investigate the effect of hypo-stoichiometry on hydrogenation properties of Laves phase dominated multiphase alloys. The samples are synthetized by arc melting and homogenizing annealing treatment. Phase abundances and lattice parameters are studied by XRD and Rietveld refinement. The morphology of each phase is confirmed by SEM and EDS, hydrogenation kinetics, pressure-composition-temperature characteristics and hydrides have been studied. Annealing increases the content of Laves phase and Zr3 V3 O, while decreases that of V-BCC and α-Zr. The decrease in atomic ratio B/A, i.e. V/(Zr + Ti), results in the increase of Zr3 V3 O, the decrease of Laves and V-BCC, and the lattice expansion for each phase. Alloys show easy activation and fast hydrogenation kinetics, which is controlled by a different process. Hydrogen absorption capacity and formation enthalpy increase while equilibrium pressure decreases with the decrease in B/A ratio, which could be related to the decrease of V-BCC phase and lattice expansion for each phase. Zr8 V16 H36.29 is the dominated hydride after saturated hydrogenation, the proportion of hydrides and their hydrogen mass fraction accord with the hydrogen absorption behavior. Among the samples, ZrTi0.1 V1.6 shows the best overall properties for rapid and massive hydrogen absorption at low pressure. Highlights: Annealing increases the content of Laves and Zr3 V3 O while decreases that of V-BCC. The decrease in B/A ratio results in the phase fraction change and lattice expansion. Hypo-stoichiometry improves absorption capacities and lowers equilibrium pressures. Surface/interface diffusion is deemed the controlling step for the fast hydrogenation. Hydrogenation behaviors are correlated to phase constitution and lattice parameters.