Effect of equal channel angular pressing (ECAP) on hydrogen storage properties of commercial magnesium alloy AZ61 Song-Jeng Huang a,* , Chun Chiu a , Tun-Yu Chou a , Eugen Rabkin b a Department of Mechanical Engineering, National Taiwan University of Science and Technology, No. 43, Keelung Rd., Sec. 4, Da'an Dist., Taipei, Taiwan, ROC b Department of Materials Science and Engineering, Technion e Israel Institute of Technology, Technion City, Haifa 3200003, Israel article info Article history: Received 3 September 2017 Received in revised form 5 January 2018 Accepted 8 January 2018 Available online xxx Keywords: Hydrogen storage Equal channel angular pressing (ECAP) Gravity casting AZ61 magnesium alloy abstract Cast commercial AZ61 magnesium alloys were processed through equal channel angular pressing (ECAP) and were comminuted into chips by filing with a rasp in order to measure their hydrogen storage properties. The effects of the number of ECAP passes and the processing route of ECAP on the hydrogen storage properties of AZ61 magnesium alloys were investigated. ECAP processing led to severe dynamic recrystallization and grain refinement of the AZ61 alloys. Of the analyzed samples, the AZ61 alloy processed via the Bc ECAP route with eight passes exhibited the smallest grain size, the fastest hydrogen ab- sorption and desorption rates, and the highest gravimetric hydrogen storage capacity of 6.2 wt%. © 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Hydrogen is considered a viable environmentally friendly alternative to fossil fuels for application in the automotive industry. Moreover, it is considered a promising energy carrier for future energy systems. However, the widespread use of hydrogen is impeded by its storage technology, especially for application in vehicles powered by fuel cells and in hydrogen- fueled internal combustion engines. Hydrogen stored in metal hydride materials exhibit advantageous characteristics such as a high volumetric storage capacity and intrinsic safety [1,2]. Metal hydrides have been considered a hydrogen storage so- lution with performance comparable with that of other stor- age options (e.g., high pressure tanks, liquefaction). To this end, among metal hydrides, magnesium hydride (MgH 2 ) is one of the most attractive candidates because of its high theoretical gravimetric capacity of 7.6 wt%, reversible hydrogen release and uptake, and relatively low cost. MgH 2 has the highest hydrogen content and hence the highest en- ergy density (9 MJ/kg of Mg) of all reversible hydrides suitable for hydrogen storage. The disadvantages of MgH 2 as a hydrogen storage material are the relatively large amount of heat required to release hydrogen, slow hydrogen absorption * Corresponding author. E-mail address: sgjghuang@mail.ntust.edu.tw (S.-J. Huang). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2018) 1 e10 https://doi.org/10.1016/j.ijhydene.2018.01.044 0360-3199/© 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Huang S-J, et al., Effect of equal channel angular pressing (ECAP) on hydrogen storage properties of commercial magnesium alloy AZ61, International Journal of Hydrogen Energy (2018), https://doi.org/10.1016/j.ijhydene.2018.01.044