Anisotropic and size-dependent mechanical responses of free-standing Ni-Nb metallic glass thin film

Abstract

Via in-situ tensile test, we demonstrated a brittle-to-ductile transition of Ni-Nb metallic glass (MG) thin films when the film thickness decreased from 363 nm to 87 nm. The elastic strain limit of 4.7% and apparent work hardening behavior were seen for free-standing 87 nm-thick film. Contrary to quenched MGs, anisotropic mechanical response existed in MG thin films with nanocolumnar structure owing to the deteriorated bonding strength of column boundaries.