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MM: Fachverband Metall- und Materialphysik
MM 9: Liquid and Amorphous Metals - Brittle-to-ductile Transition
MM 9.3: Vortrag
Montag, 16. März 2020, 12:15–12:30, IFW D
Boron concentration induced Co-Ta-B composite formation observed in the transition from metallic to covalent glasses — •Simon Evertz1, Stephan Prünte1, Lena Patterer1, Marshal Amalraj1, Damian M. Holzapfel1, Alexander Schökel2, Marcus Hans1, Daniel Primetzhofer3, and Jochen M. Schneider1 — 1Materials Chemistry, RWTH Aachen University, Aachen, Germany — 2Deutsches Elektronen Synchrotron DESY, Hamburg, Germany — 3Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
Due to their unique property combination of high strength and toughness, metallic glasses are promising materials for structural applications. As the behaviour of metallic glasses depends on the electronic structure which in turn is defined by chemical composition, we investigate systematically the influence of B content on glass transition, topology, magnetism and bonding for B contents between 2 and 92 at% in the (Co6.8Ta1)1−xBx system. From an electronic structure and coordination point of view the B concentration range is divided into three regions: Below 38 ± 5 at% B, the material is a metallic glass due to the dominance of metallic bonds. Above 67 ± 5 at% the presence of an icosahdra-like B-network is observed. As the B concentration is increased above 38 ± 5 at%, the B-network evolves while the metallic coordination of the material decreases until the B concentration of 67 ± 5 at% is reached. Hence, a composite is formed. It is evident that based on the B concentration the ratio of metallic bonding to icosahedral bonding in the composite can be controlled.