Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 2: Topical session (Symposium MM): High entropy and compositionally complex alloys
MM 2.1: Topical Talk
Monday, April 1, 2019, 10:15–10:45, H43
Fundamentals of deformation in high- and medium-entropy alloys — •Guillaume Laplanche1, Joël Bonneville2, Céline Varvenne3, Aleksander Kostka4, William A. Curtin5, and Easo P. George6 — 1Institut für Werkstoffe, Ruhr-Universität Bochum, Germany — 2Institut PPRIME, University of Poitiers, France — 3CINaM, Aix-Marseille Univ. - CNRS, Marseille, France — 4Materials Research Department and Center for Interface Dominated Materials (ZGH), Ruhr-University Bochum, Germany — 5Institute of Mechanical Engineering, EPFL, Lausanne, Switzerland — 6Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, USA
High-entropy alloys (HEAs) consists of five or more elements in near-equiatomic proportions and crystallize as single-phase solid solutions. This presentation focuses on one of the most thoroughly investigated HEAs, namely, the fcc CrMnFeCoNi alloys. These alloys have been shown to exhibit fascinating mechanical properties, including increasing tensile ductility and strength with decreasing temperature, with composition having a strong effect. In this presentation, two model alloys: CrMnFeCoNi (HEA) and CrCoNi (medium-entropy alloy), are selected to explain key microstructural aspects responsible for strength, ductility, and work-hardening rate. As both alloys deform by dislocation plasticity initially and deformation twinning after a critical stress has been reached, evolutions with deformation of dislocation and twin microstructures as well as activation volumes are used to identify the mechanisms responsible for macroscopic mechanical behaviors.