Effects of heat treatment on microstructure, hardness and local structure in a compositionally complex alloy
- Unlike conventional alloys, high entropy alloys are characterized by one or more solid solution phase(s) without a clearly defined solvent, all element contribute to the matrix in a way that is still not entirely understood. In addition, it is not known to what extent classic thermodynamic rules can be applied to these multi-element alloys, especially concerning the question about what factor incites the matrix to undergo a phase transformation. This work tackles directly some of these aspects on a chosen alloy, Al8Cr17Co17Cu8Fe17Ni33 (at.%), which presents a high temperature single-phase γ state and a two-phase state with γ′ precipitates, above and below 900 ◦C, respectively. A combined investigation via microstructural observations, hardness testing, X-ray absorption and photoelectron spectroscopy was carried out above the γ′ formation temperature. Hardness values are independent of the annealing temperatures, microstructural analysis shows no phase formation and X-ray absorptionUnlike conventional alloys, high entropy alloys are characterized by one or more solid solution phase(s) without a clearly defined solvent, all element contribute to the matrix in a way that is still not entirely understood. In addition, it is not known to what extent classic thermodynamic rules can be applied to these multi-element alloys, especially concerning the question about what factor incites the matrix to undergo a phase transformation. This work tackles directly some of these aspects on a chosen alloy, Al8Cr17Co17Cu8Fe17Ni33 (at.%), which presents a high temperature single-phase γ state and a two-phase state with γ′ precipitates, above and below 900 ◦C, respectively. A combined investigation via microstructural observations, hardness testing, X-ray absorption and photoelectron spectroscopy was carried out above the γ′ formation temperature. Hardness values are independent of the annealing temperatures, microstructural analysis shows no phase formation and X-ray absorption spectroscopy does not reveal observable changes in neither local atomic nor electronic structure, indicating that approaching γ′ formation temperature is not influenced by atomic or electronic rearrangements. Interestingly, short-range chemical order remains quantitatively compatible at any annealing temperature in the single-phase γ state, and the observed preferred pairs Al–Cu and Al–Ni in the γ state match with the γ’ precipitates composition below 900 ◦C.…
Autor*innen: | Andrea FantinORCiD, Cafer Tufan CakirORCiD, S. KasatikovORCiD, G. SchumacherORCiD, Anna Maria ManzoniORCiD |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Materials Chemistry and Physics |
Jahr der Erstveröffentlichung: | 2022 |
Organisationseinheit der BAM: | 5 Werkstofftechnik |
5 Werkstofftechnik / 5.1 Mikrostruktur Design und Degradation | |
6 Materialchemie | |
6 Materialchemie / 6.3 Strukturanalytik | |
Verlag: | Elsevier B.V. |
Jahrgang/Band: | 276 |
Erste Seite: | 125432 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Freie Schlagwörter: | EXAFS; High entropy alloys; Short range order; Vickers hardness |
Themenfelder/Aktivitätsfelder der BAM: | Material |
DOI: | 10.1016/j.matchemphys.2021.125432 |
ISSN: | 0254-0584 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 17.11.2021 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 09.12.2021 |