Shkodich, Natalia ; Staab, Franziska ; Spasova, Marina ; Kuskov, Kirill V. ; Durst, Karsten ; Farle, Michael (2022)
Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys.
In: Materials, 15 (20)
doi: 10.3390/ma15207214
Artikel, Bibliographie
Dies ist die neueste Version dieses Eintrags.
Kurzbeschreibung (Abstract)
In our search for an optimum soft magnet with excellent mechanical properties which can be used in applications centered around “electro mobility”, nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) bulk high entropy alloys (HEA) were successfully produced by spark plasma sintering (SPS) at 1073 K of HEA powders produced by high energy ball milling (HEBM). SPS of non-equiatomic CoCrFeNiGa₀.₅ particles results in the formation of a single-phase fcc bulk HEA, while for the equiatomic CoCrFeNiGa composition a mixture of bcc and fcc phases was found. For both compositions SEM/EDX analysis showed a predominant uniform distribution of the elements with only a small number of Cr-rich precipitates. High pressure torsion (HPT) of the bulk samples led to an increased homogeneity and a grain refinement: i.e., the crystallite size of the single fcc phase of CoCrFeNiGa₀.₅ decreased by a factor of 3; the crystallite size of the bcc and fcc phases of CoCrFeNiGa—by a factor of 4 and 10, respectively. The lattice strains substantially increased by nearly the same extent. After HPT the saturation magnetization (Ms) of the fcc phase of CoCrFeNiGa₀.₅ and its Curie temperature increased by 17% (up to 35 Am²/kg) and 31.5% (from 95 K to 125 K), respectively, whereas the coercivity decreased by a factor of 6. The overall Ms of the equiatomic CoCrFeNiGa decreased by 34% and 55% at 10 K and 300 K, respectively. At the same time the coercivity of CoCrFeNiGa increased by 50%. The HPT treatment of SPS-consolidated HEAs increased the Vickers hardness (Hv) by a factor of two (up to 5.632 ± 0.188) only for the non-equiatomic CoCrFeNiGa₀.₅, while for the equiatomic composition, the Hv remained unchanged (6.343–6.425 GPa).
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Shkodich, Natalia ; Staab, Franziska ; Spasova, Marina ; Kuskov, Kirill V. ; Durst, Karsten ; Farle, Michael |
| Art des Eintrags: | Bibliographie |
| Titel: | Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys |
| Sprache: | Englisch |
| Publikationsjahr: | 2022 |
| Ort: | Darmstadt |
| Verlag: | MDPI |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Materials |
| Jahrgang/Volume einer Zeitschrift: | 15 |
| (Heft-)Nummer: | 20 |
| Kollation: | 15 Seiten |
| DOI: | 10.3390/ma15207214 |
| Zugehörige Links: | |
| Kurzbeschreibung (Abstract): | In our search for an optimum soft magnet with excellent mechanical properties which can be used in applications centered around “electro mobility”, nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) bulk high entropy alloys (HEA) were successfully produced by spark plasma sintering (SPS) at 1073 K of HEA powders produced by high energy ball milling (HEBM). SPS of non-equiatomic CoCrFeNiGa₀.₅ particles results in the formation of a single-phase fcc bulk HEA, while for the equiatomic CoCrFeNiGa composition a mixture of bcc and fcc phases was found. For both compositions SEM/EDX analysis showed a predominant uniform distribution of the elements with only a small number of Cr-rich precipitates. High pressure torsion (HPT) of the bulk samples led to an increased homogeneity and a grain refinement: i.e., the crystallite size of the single fcc phase of CoCrFeNiGa₀.₅ decreased by a factor of 3; the crystallite size of the bcc and fcc phases of CoCrFeNiGa—by a factor of 4 and 10, respectively. The lattice strains substantially increased by nearly the same extent. After HPT the saturation magnetization (Ms) of the fcc phase of CoCrFeNiGa₀.₅ and its Curie temperature increased by 17% (up to 35 Am²/kg) and 31.5% (from 95 K to 125 K), respectively, whereas the coercivity decreased by a factor of 6. The overall Ms of the equiatomic CoCrFeNiGa decreased by 34% and 55% at 10 K and 300 K, respectively. At the same time the coercivity of CoCrFeNiGa increased by 50%. The HPT treatment of SPS-consolidated HEAs increased the Vickers hardness (Hv) by a factor of two (up to 5.632 ± 0.188) only for the non-equiatomic CoCrFeNiGa₀.₅, while for the equiatomic composition, the Hv remained unchanged (6.343–6.425 GPa). |
| Freie Schlagworte: | high entropy alloy, high energy ball milling, spark plasma sintering, high pressure torsion, coercivity, Vickers hardness |
| Zusätzliche Informationen: | This article belongs to the Special Issue Spark Plasma Sintered Materials with Advanced Properties |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik 500 Naturwissenschaften und Mathematik > 540 Chemie 600 Technik, Medizin, angewandte Wissenschaften > 660 Technische Chemie |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Physikalische Metallkunde |
| Hinterlegungsdatum: | 06 Dez 2023 09:51 |
| Letzte Änderung: | 06 Dez 2023 09:51 |
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| Suche nach Titel in: | TUfind oder in Google |
Verfügbare Versionen dieses Eintrags
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Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys. (deposited 07 Nov 2022 12:26)
- Effect of High-Pressure Torsion on the Microstructure and Magnetic Properties of Nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys. (deposited 06 Dez 2023 09:51) [Gegenwärtig angezeigt]
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