Editors: | F. Kongoli, S. Kobe, M. Calin, J.-M. Dubois, T. Turna |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 154 pages |
ISBN: | 978-1-987820-90-4 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Magnesium alloys as ZK60 are interesting materials for hydrogen storage in the solid state, due to the high volumetric and gravimetric capacities that can be attained, and to the relatively low relative cost of these materials. The development of simpler and more cost effective processing routes of Mg alloys for H2 storage is an important challenge of applied research, in order to make possible the replacement of the intensive time and energy consuming processes based on high-energy ball milling, HEBM. We have explored different alternatives of advanced processing to ZK60 or ZK60 modified with Mm (mischmetal) [1-3], aiming to produce refined microstructures and enhanced H2 storage properties, especially faster activation (first hydrogenation) kinetics. Due to the Mm addition, a network of intermetallic particles is formed at the grain boundaries of the modified ZK60 alloy. Equal-channel angular pressing (ECAP) or rapid solidification by melt-spinning (MS) were combined with a subsequent step of extensive cold rolling (CR). The additional processing by CR caused further grain refinement and breakage of intermetallic particles, as well as favoring crystallographic texture in the (002) direction. All these features promoted a significant improvement in the hydrogen storage capacity. Another approach applied for the ZK60 alloy consisted in the combination of friction stir processing (FSP) with filing. The pulverization of the ZK60 alloy, already grain refined by FSP, has shown to be also an interesting strategy to produce materials with better H-absorption/desorption kinetics.