Reactive milling and hydrogen storage properties of high entropy alloys of the Mg-...
| Grant number: | 16/13885-9 |
| Support type: | Scholarships in Brazil - Post-Doctorate |
| Effective date (Start): | September 01, 2017 |
| Effective date (End): | October 08, 2018 |
| Field of knowledge: | Engineering - Materials and Metallurgical Engineering - Physical Metallurgy |
| Principal Investigator: | Daniel Rodrigo Leiva |
| Grantee: | Erenilton Pereira da Silva |
| Home Institution: | Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil |
| Associated research grant: | 13/05987-8 - Processing and characterization of amorphous, metastable and nano-structured metallic alloys, AP.TEM |
Abstract The main technological challenge for the wider application of hydrogen as an energy carrier is the development of appropriate solutions for its storage. The use of metal hydrides, which store hydrogen in solid form, is a more effective and safe alternative to H2 under high pressure or liquefied. MgH2 has the highest gravimetric capacity among all metal hydrides, of 7.6%. Currently, two main types of processing routes are considered to produce Mg-based mixtures for hydrogen storage: the ones based on high energy milling (HEBM), or alternatively in severe plastic deformation (SPD). It is observed that milled powders have a higher reactivity with hydrogen that severelydeformed bulk samples, which is explained for the largest microstructural refinementand higher specific surface area attained. However, the cost of the material produced bySPD is supposed to be much lower, since the time and energy involved in processingare reduced. Thus, the development of a SPD route to produce Mg alloys with enhancedhydrogen storage properties is an important question of applied research. In thisproposal, the ZK60 alloy modified with 2.5 wt% Mm (mischmetal) was selected for experiments involving mechanical processing by hot rolling (HR), extensive cold rolling (CR) and equal-channel angular pressing (ECAP). The goal is to achieve better control of microstructure and texture obtained and so prepare the material for final processing by filing, which has significant impact on the reactivity of the material with hydrogen, to substantially increase the contact area with the H2. The microstructural changes introduced by filing will be evaluated in detail for the first time in a hydrogen storage study. Thus, the aim is to produce, with low cost, Mg-based alloys withimproved kinetic properties of hydrogen absorption / desorption, by effective control of processing conditions. | |