Size-dependent failure mechanisms in ZrNi thin metallic glass films

The fracture toughness of submicron Zr65Ni35 sputter-deposited films is thickness dependent. The failure mechanism involves corrugations for the thickest films and a transition-at 500 nm thickness-to a perfectly flat fracture surface. Both mechanisms are brittle-type, even though the elastic and plastic properties are independent of thickness and similar to the expected ductile bulk response. Finite-element simulations unravel the origin of the size effect and the transition of failure mode from the constraint on plastic dissipation. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.