Abstract
The effects of hydrogen addition on the structural and mechanical properties of Zr57Al10Cu15.4Ni12.6Nb5 amorphous metallic alloy were analysed. Structural investigation, using x-ray diffraction, revealed that hydrogen addition causes the development of large void and structural expansion. By means of nanoindentation tests, it has been shown that hydrogen addition can induce either softening or hardening of Zr-based amorphous alloys depending on the extent of the hydrogen content and mobility. The shear softening of amorphous material is due to the weakness of atomic cohesion attributed to the squeezing of 'mobile' hydrogen atoms. When hydrogen content grows excessive, strongly bounded 'immobile' atoms form a densely packed structure that restrict the local atomic movement and consequently harden the amorphous material alloy.