Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 36: Liquid and Amorphous Metals
MM 36.9: Talk
Thursday, April 4, 2019, 12:30–12:45, H46
Design of thin film metallic glasses with superior fracture toughness — •Simon Evertz1, Ines Kirchlechner2, Rafael Soler2, Christoph Kirchlechner2, Paraskevas Kontis2, Volker Schnabel3, Gerhard Dehm2, Dierk Raabe2, and Jochen M. Schneider1 — 1Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany — 2Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40237 Düsseldorf, Germany — 3Laboratory for Nanometallurgy, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
Damage tolerance, i.e. the combination of high yield strength and fracture toughness, is crucial for the application of metallic glasses as structural materials. One fingerprint for damage tolerance in metallic glasses is the fraction of hybridized bonds (Schnabel et al., Scientific Reports 6 (2016) 36556), which is affected by alloying Pd57.4Al23.5Y7.8M11.3 with M = Fe, Co, Ni, Cu, Os, Ir, Pt and Au. Based on these ab initio calculations, the minimum fracture toughness was identified for Pd57.4Al23.5Y7.8Ni11.3. Furthermore, it is shown that by correlating experimental fracture toughness data to the fraction of hybridized bonds scaling with the crystal orbital overlap population at the Fermi level, the fracture toughness can be estimated based on electronic structure data. The fracture toughness of Pd57.4Al23.5Y7.8Ni11.3 is predicted to be in the range of 90 to 150 MPa.m0.5 exhibiting a plastic zone size of 0.1 to 1 mm, which is consistent with micro-mechanical beam bending experiments, where fracture was not observed.