Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 68: Transport (Diffusion, conductivity, heat)

MM 68.1: Vortrag

Donnerstag, 15. März 2018, 17:30–17:45, TC 010

Radiotracer self-diffusion experiments in CoCrFeNi and CoCrFeMnNi high entropy alloy single crystals — •Daniel Gaertner¹, Jonas Lübke¹, Josua Kottke¹, Yury Chumlyakov², Gerhard Wilde¹, and Sergiy Divinski¹ — ¹Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — ²Department of Physics of Metals, Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia

High entropy alloys are multicomponent alloys, which have a large number of constituting elements in equiatomic or nearly equiatomic concentrations. These materials are hypothesized to show significantly decreased self diffusivities. For the first time, diffusion of all constituent elements in equiatomic CoCrFeNi and CoCrFeMnNi single crystals is investigated using the radiotracer technique, thereby the tracer diffusion coefficients of Cr-51, Co-57, Fe-59, Mn-54 and Ni-63 are determined at a temperature of 1100 °C. Two contributions to the long-range atom transport are observed and their nature is elucidated by varying the diffusion times. In addition to the bulk diffusion transport, short-circuit diffusion seems to be prominent due to a high density of grown-in dislocations. The components are characterized by significantly different diffusion rates, with Mn being the fastest element and Ni and Co being the slowest ones.