Regensburg 2019 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 12: Poster session I
MM 12.32: Poster
Monday, April 1, 2019, 19:15–20:45, Poster C
Grain-boundary diffusion in CoCrFeNi and CoCrFeMnNi high entropy alloy polycrystals — •Marcel Glienke1, Mayur Vaidya1, Lukasz Rogalc2, Sergiy Divinski1, and Gerhard Wilde1 — 1Westfälische-Wilhelms Universität, Institut für Materialphysik, Münster, Deutschland — 22Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 30-059 Krakow, Poland
For the first time, grain boundary (GB) diffusion of Co, Cr, Fe and Mn have been measured in polycrystalline CoCrFeNi and CoCrFeMnNi high entropy alloys (HEAs) using the radiotracer technique. The alloys have been prepared using high frequency electromagnetic induction melting followed by homogenization at 1200°C for 50 h. X-ray diffraction confirms the single phase FCC structure of both the HEAs. Scanning electron microscopy along with electron back-scattered diffraction (EBSD) validates the equiatomic composition and coarse grained microstructures. Radioactive isotopes 57Co, 51Cr, 59Fe and 54Mn have been utilized to measure grain boundary self-diffusion in the temperature range of 800°C - 1000°C. The temperature and time of diffusion annealing are selected to ensure the B-type kinetics conditions for both the HEAs. The temperature dependence of the GB diffusion coefficients follows Arrhenius behavior for all the constituents in the HEAs. The obtained results are compared on the homologous temperature scale with GB self-diffusivities in other FCC matrices.