Regensburg 2025 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: Transport in Materials: Diffusion, Charge or Heat Conduction

MM 35.1: Vortrag

Freitag, 21. März 2025, 10:15–10:30, H22

Influence of second phase precipitation on bulk diffusion of Ni in the CoFeMnNiV high-entropy alloy — •Aditya Burla¹, Mohan Muralikrishna Garlapati¹, Aditya Srinivasan Tirunilai², Guillaume Laplanche², Gerhard Wilde¹, and Sergiy V Divinski¹ — ¹Institut für Materialphysik, Universität Münster, 48149 Münster, Germany — ²Institut für Werkstoffe, Ruhr-Universität Bochum, 44780 Bochum, Germany

High-entropy alloys (HEAs), or multi-principal element alloys represent a new class of metallic materials that offer tremendous opportunities for advancing materials science due to their vast compositional space and exceptional properties. While tracer diffusion and sigma phase precipitation kinetics in the Co-Cr-Fe-Mn-Ni system have been widely studied, the interaction between the two has received limited attention. The present work focuses on an equiatomic CoFeMnNiV HEA, in which Vanadium is known to have a strong tendency to stabilize the sigma phase. Therefore, this element promotes its precipitation in the CoFeMnNiV alloy, particularly at temperatures below ~1080°C, even after short anneal times of just 1 h in the fully recrystallized state. In this study, bulk diffusion of Ni is investigated using the radiotracer technique. A strong impact of sigma phase precipitation on the self-diffusion kinetics was discovered and analyzed. The obtained tracer diffusivities follow an Arrhenius-type relationship when estimated in the stable microstructures, whereas concurrent precipitation enhances the tracer diffusion rates.

Keywords: High entropy alloys; Radiotracer technique; Diffusion kinetics; Sigma phase; Dual phase high entropy alloys