Effect of microstructure on the phase composition and hydrogen absorption-desorption behaviour of melt-spun Mg-20Ni-8Mm alloys

► Rapid solidification (RS) of Mg-Ni-Mm alloy alters microstructure and H sorption. ► RS results in decrease of unit cell volumes of the constituent hydride phases. ► RS results in formation of HT-Mg2NiH4 and Mg2NiH0.3, instead of LT-Mg2NiH4. ► Increase of RS rate results in improvement of H absorption/desorption kinetics. ► Increase of RS rate results in narrowing temperature range for H thermal desorption.