SKM 2023 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 41: Topical Session: Defect Phases III
MM 41.4: Talk
Thursday, March 30, 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.