SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 40: Mechanical Properties and Allloy Design
MM 40.10: Vortrag
Donnerstag, 30. März 2023, 18:15–18:30, SCH A 251
Magnetism in nanocrystalline CoMnFeNiGa high entropy alloys: "from micro and bulk to nano" — •Natalia Shkodich1,2, Varatharaja Nallathambi1,2, Tatyana Smolyarova1, Sven Reichenberger1, and Michael Farle1 — 1Faculty of Physics and Center of Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg, 47057 Germany — 2Max-Planck-Institut für Eisenforschung Max-Planck-Straße 1, 40237 Düsseldorf, Germany
We report the successful fabrication of three types of CoMnFeNiGa high entropy alloys: a) nanoparticles, b) nanocrystalline micron-sized powder, and c) nanocrystalline metallic bulk. Homogeneous micron-sized CoMnFeNiGa HEA powders with a nanocrystalline structure and compositional homogeneity were produced by high energy ball milling (HEBM) for 190 min in Ar at 900/1800 rpm. From these powders we synthesized (a) homogeneous nanocrystalline bulk HEAs by spark plasma sintering (SPS) and (b) HEA nanoparticles - by laser fragmentation in liquids (LFL). The XRD, SEM/EDX, and HR TEM results showed that single fcc phase nanosized grains (~10 nm) are obtained after 190 min of HEBM. These partially transform into a bcc one after SPS at 1073K, while the LFL leads to the formation of nanoparticles with two morphologies, that is spheres and platelets with fcc, bcc and hexagonal structures. Fast annealing up to 1000K of HEBM and LFL HEA particles leads to significant structural and composition changes and increases the saturation magnetization Ms (300K) from 35.4 to 96.1 Am2/kg, and from 37.3 to 49.7 Am2/kg, respectively. We acknowledge financial support from DFG (CRC/TRR 270, project S01).