Nano-laminated thin film metallic glass design for outstanding for mechanical properties

We report the enhancement of fracture toughness and strength of a cobalt tantalum-based metallic glass thin film with increasing boron content. The improvement of the mechanical performance is attributed to the formation of a compositionally lamellar compared to uniform glass microstructure, which becomes thinner with increasing boron content as revealed by transmission electron microscopy. Compositional variations across the lamellar structure are revealed by atom probe tomography. Cobalt- and boron-rich regions alternate sequentially, whereas tantalum exhibits slight variations across the lamellae. Our results can be utilized in future design efforts for metallic glass thin films with outstanding mechanical performance. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.