Hydrogen storage in heavily deformed ZK60 alloy modified with 2.5 wt.% Mm addition

Abstract

Severe plastic deformation techniques have been extensively used to improve hydrogen storage properties of magnesium based alloys. In this work, the commercial magnesium alloy ZK60 (Mg-6Zn-1Zr in wt.%) was modified with addition of 2.5 wt.% of mischmetal (55Ce-24La-15Nd-4Pr in wt.%) and subsequently processed by equal-channel angular pressing (ECAP) and extensive cold rolling (CR). Due to the mischmetal addition, a network of intermetallic particles was formed at the grain boundaries. Besides Zn and Zr, the particles also contained the rare-earth elements La and Ce. With CR, a breakage of intermetallics occurred, that could also have played a role in enhancing the hydrogen storage properties. Ultimately, after the combined processing of ECAP followed by CR cold rolling, a significant increase in the storage capacity and activation kinetics was observed.