Low temperature de/hydrogenation in the partially crystallized Mg60Ce10Ni20Cu10 metallic glasses induced by milling with process control agents

Abstract Slow hydrogen de/absorption kinetics and high hydrogen desorption temperature are still great challenges for both crystalline and amorphous Mg-based alloys. In this work, through using ethanol (E) and ethylene glycol (EG) as milling process control agents (PCAs), partial and controllable crystallization of the melt-spun Mg 60 Ce 10 Ni 20 Cu 10 metallic glass was achieved. The microstructure of the as-milled powders and corresponding hydrides was characterized by DSC, SEM, TEM and XRD. De/hydrogenation properties were measured by automatic Sieverts-type apparatus and TG-MS. It was found that the PCAs could lead to partial crystallization of the Mg 60 Ce 10 Ni 20 Cu 10 metallic glass due to the dissolving of oxygen into the amorphous structure from PCAs. The introduction of a small amount of the nanocrystals promoted greatly hydrogen de/absorption properties of the melt-spun Mg 60 Ce 10 Ni 20 Cu 10 alloy. The hydrogenation temperature could be decreased to below 100 °C and the initial hydrogen desorption temperature of the EG-added hydride could be decreased to below 150 °C. The structure evolution of the de/hydrogenated samples of the EG-added powder was also studied. The hydrogen-induced crystallization was evidently observed in the hydrogenated sample. The ethanol and ethylene glycol was found to be effective milling PCAs to create a composite structure of amorphous and crystalline, and the composite structure greatly enhanced the de/hydrogenation properties. However, the structural stability and reversibility of such composite structure during hydrogenation were still great challenges.