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MM: Fachverband Metall- und Materialphysik

MM 36: Mechanical Properties

MM 36.10: Vortrag

Freitag, 21. März 2025, 12:45–13:00, H23

Ferromagnetism at ambient temperature in Cantor and nanocomposite high-entropy alloys induced by severe plastic deformation — •Shabnam Taheriniya, Harald Rösner, and Gerhard Wilde — Universität Münster, Institut für Materialphysik, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

In this study, single phase Cantor (CoCrFeMnNi) and nanocomposite high-entropy alloys (HEAs) (CoCrFeMnNi and HfNbTaTiZr) were processed using high-pressure torsion (HPT), subjecting the samples to a constant pressure of 9 GPa either as a single disk or stacked disks, with the top anvil rotating at 1 rpm at ambient temperature for up to 15 revolutions. Vibrating sample magnetometry (VSM) confirmed that HPT processing induces the development of ferromagnetic properties. The distribution and orientation of magnetic domains post-deformation were examined in detail using differential phase contrast scanning transmission electron microscopy (DPC STEM), analytical TEM and atom probe tomography (APT) analysis. Our study demonstrates that HPT processing of HEAs induces a transition from paramagnetic to ferromagnetic states at ambient conditions. This deformation-induced ferromagnetism can be explained by the cocktail effect in HEAs, where the formation of ferromagnetic particles is linked to deformation-induced element-selective atomic migration and local enrichment of ferromagnetic elements.

Keywords: High Entropy Alloys; Severe Plastic Deformation; Ferromagentism; Differential Phase Conrast Microscopy; Nanocomposite