Local lattice distortions and chemical short-range order in MoNbTaW

Autor: Andrea Fantin, Anna Maria Manzoni, Hauke Springer, Reza Darvishi Kamachali, Robert Maaß
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Materials Research Letters, Vol 12, Iss 5, Pp 346-354 (2024)
Druh dokumentu: article
ISSN: 21663831
2166-3831
DOI: 10.1080/21663831.2024.2326014
Popis: Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, [Formula: see text], is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO.
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