SKM 2023 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Topical Session: Defect Phases III

MM 41.4: Vortrag

Donnerstag, 30. März 2023, 16:45–17:00, SCH A 216

Non-Arrhenius temperature dependence of grain boundary diffusion in additively manufactured high-entropy CoCrFeMnNi alloy — •Nuri Choi¹, Manoel W. da Siva Pinto¹, Saba Khademorezaian¹, Sangsun Yang², Ji Hun Yu², Jai Sung Lee³, Gerhard Wilde¹, and Sergiy V. Divinski¹ — ¹Institute of Material Physics, University of Münster, Münster, Germany — ²Center for 3D Printing Materials Research, Korea Institute of Materials Science, Changwon, South Korea — ³Dep. of Mat. Sci. & Chem. Eng., Hanyang University, Ansan, South Korea

Additive manufacturing process induces numerous crystalline defects such as vacancies, dislocations and dislocation networks, non-equilibrium segregation which affect mechanical, kinetic and structural properties of the fabricated materials. Moreover, a non-equilibrium state of grain boundaries has been discovered, too, which is characterized by enhanced rates of grain boundary diffusion at relatively low temperatures [1]. In the present study, grain boundary diffusion of Ni in additively manufactured CoCrFeMnNi high-entropy alloys is measured in an extended temperature interval. A non-monotonous temperature dependence is observed and interpreted in terms of a thermally-activated relaxation of the non-equilibrium state. The grain boundary energy is evaluated from the grain boundary diffusivity data for various heat-treatment conditions and compared to the total energy released during annealing by differential scanning calorimetry. The evolution of microstructure and mechanical properties is discussed, too.