Fracture toughness study of new Zr-based Be-bearing bulk metallic glasses

Abstract

Three new compositional variants of the Zr-Ti-Be-LTM (late transition metal) family of metallic glasses are discussed. Thermal stability Delta T=T-x-T-g, was increased from 82 degrees C for Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Viterloy 1) to 141 degrees C for Zr44Ti11Cu20Be25. It is found that fracture toughness is the most distinguishing parameter characterizing the alloys in contrast to other mechanical properties. Quaternary alloys consistently had fracture toughness values exceeding 80 MPa m(1/2), while for Vitreloy 1 K-Q = 48.5 MPa m(1/2) with a large amount of scatter. Adding iron reduced the fracture toughness to 25 MPa m(1/2). (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.