Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 12: Poster session I

MM 12.35: Poster

Monday, April 1, 2019, 19:15–20:45, Poster C

Grain-boundary diffusion in CoCrFeNi and CoCrFeMnNi high entropy alloybi-crystals — •Alexandra Everwand¹, Daniel Gaertner¹, Bengü Tas¹, Yury Chumlyakov², Gerhard Wilde¹, and Sergiy V. Divinski¹ — ¹Institute of Materials Physics, University of Münster, Münster, Germany — ²Department of Physics of Metals, Tomsk State University, Tomsk, Russia.

The diffusion kinetics in the equiatomic quaternary CoCrFeNi and quinary CoCrFeMnNi high entropy alloys, the so-called Cantor-alloys, were previously investigated using the radiotracer technique in single- and poly-crystalline materials. For the first time, diffusion of all constituent elements and additionally solute diffusion of Mn in the quaternary alloy is investigated in bi-crystalline HEAs with a defined grain-boundary. In order to define the microstructure, the chemical composition of the bi-crystals and the grain-boundary structure, scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) analyses are performed. Using the radiotracer technique, the grainboundary diffusion coefficients of ⁵⁷Co, ⁵¹Cr, ⁵⁹Fe, ⁵⁴Mn and ⁶³Ni are determined at a temperature of 1373 K according to Harrison’s B-type, and at a temperature of 923 K according to Harrisons’s C-type. The components are characterized by significantly different diffusion rates, with Mn being the fastest element and Ni and Co being the slowest ones.