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

Three new compositional variants of the Zr–Ti–Be–LTM (late transition metal) family of metallic glasses are discussed. Thermal stability, ΔT = Tx−Tg, was increased from 82 °C for Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Viterloy 1) to 141 °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 m1/2, while for Vitreloy 1 KQ = 48.5 MPa m1/2 with a large amount of scatter. Adding iron reduced the fracture toughness to 25 MPa m1/2.