Effects of equal-channel angular pressing and accumulative roll-bonding on hydrogen storage properties of a commercial ZK60 magnesium alloy

• Commercial ZK60 magnesium alloy was processed by ECAP and ARB for hydrogen storage.
• Low surface to volume ratio of the ECAP plus ARB samples limits storage capacity.
• Faster kinetics and higher storage capacity is produced by pulverization of samples.

The hydrogen storage properties of a commercial ZK60 magnesium alloy were investigated after processing by equal-channel angular pressing (ECAP) and accumulative roll-bonding (ARB). Samples were prepared by 6 passes of ECAP and subsequently rolled 25 times. Microstructural characterization was performed using scanning and transmission electron microscopy. The kinetics of hydrogen absorption and desorption were measured in a Sievert-type apparatus. Processing only by ECAP resulted in a very low hydrogen storage capacity of 0.5 wt. %. Additional processing by ARB refined the microstructure and improved the hydrogen absorption. Despite this improvement, the hydrogen capacity was limited to less than 4 wt. %. This limitation was overcome by crushing the materials into small thin plates. The crushed sample from the ECAP material absorbed 4.77 wt. % of hydrogen in 24 h while the capacity of the sample processed by ECAP and ARB was 6.4 wt. %. The results are discussed in terms of morphology and microstructure of the samples.