Hydrogen Storage Properties of the Ti18V24Nb23Cr33Al2 Multicomponent Alloy Using Ti6V4Al Alloy Scraps as Feedstock Material

Abstract

Hydrogen storage in metal hydrides has been extensively studied due to their capacity to reversibly absorb hydrogen under relatively low pressures. Multicomponent alloys, especially those of the Ti-V-Nb-Cr system, have garnered significant attention because of the possibility of fine-tuning the hydrogen storage properties by compositional control. However, most of the investigations on multicomponent alloys rely on high-purity elements as feedstock materials, which can have a substantial environmental impact due to the energy-intensive processes required to achieve such purity levels. In this work, we propose an alternative approach by utilizing Ti6Al4V alloy (ASTM F136) scraps from the biomedical industry as feedstock material to produce Ti₁₈Nb₂₃V₂₄Cr₃₃Al₂. The alloy was synthesized by using an arc-melting process, combining Ti6Al4V scraps with other pure elements. Structural analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed the formation of a microstructure composed predominantly by a body-centered cubic (BCC) solid solution with a small micro segregation providing additional microstructural insights. The Ti₁₈Nb₂₃V₂₄Cr₃₃Al₂ alloy exhibited a hydrogen storage capacity of 2.75 wt % H₂ with room temperature reversibility, presenting hydrogen storage properties comparable to those of a (TiVNb)₆₅Cr₃₅ alloy produced only from high-purity elements.

This study presents a sustainable approach to producing Ti₁₈Nb₂₃V₂₄Cr₃₃Al₂ alloy from Ti6Al4V machine chips, achieving efficient hydrogen storage with reduced environmental impact.