Cold rolling of titanium alloys for hydrogen storage

Abstract

Hydrogen is a very interesting energy carrier, considering its high calorific value, its suitability for use in fuel cells and the generation of water as by-product. The storage of hydrogen in metal hydrides in the solid state is a promising alternative to gaseous and liquid forms, for increased security and higher gravimetric and volumetric capacities of storage. Among hydrogen storage materials, Ti alloy consisting of BCC solid solutions based on the Ti - Cr - V system are competitive because they have significant storage capacity, reaching 3.5% by weight, and absorb hydrogen at low temperatures, near room temperature. Nb has been considered as a substitute of V considering its affinity with hydrogen and lower cost. Processing by mechanical alloying (HEBM, high-energy ball milling) has been established as an effective alternative for the preparation of nanocomposites for hydrogen storage applications. However, the use of HEBM techniques requires high energy and time consumption for the preparation of powders, which are extremely reactive to air, demanding their manipulation in controlled atmosphere. In this project, we propose the systematic study of extensive cold rolling as the processing route for Ti alloys, in the systems Ti - Nb, Ti - Cr - V and Ti - Cr - Nb, in order to produce materials with properties in short time, with interesting H2 absorption/desorption kinetics, and still counting with the additional benefit of air resistance. The microstructural analysis results and H2 storage properties will be compared for those obtained for similar samples produced by HEBM. The main benefit expected in this proposal is the development of low cost processing routes for the production of titanium alloys with microstructures and properties suitable for hydrogen storage.