B2 ordering in body-centered-cubic AlNbTiV refractory high-entropy alloys

Machine learning for high-entropy alloys: Progress, challenges and opportunities

“…The lattice distortion effect ignored in the rigid-lattice model was included by using DFT-relaxed structures. They found that the lattice relaxation is important for MoNbTaW when the temperature is below 500 K. Using the same approach, Kostituchenko and Körmann et al also investigated the short-range order in BCC AlNbTiV [170] and FCC VCoNi [169]. For AlNbTaV, their calculations reveal a B2 ordering below 1700 K, which is mainly caused by the site preference of Al and Ti atoms.…”

Simulating short-range order in compositionally complex materials

“…As most of these techniques have been developed only very recently, the majority of SRO investigations discussed in the following were performed based on explicit DFT calculations. SRO has been observed in many CCMs, including (1) the famous Cantor alloy, CrMnFeCoNi, and some of its subsystems 37,66,67 , also with the addition of Al 68,69 , Cu 70 or Pd 71 ; (2) alloys of the refractory elements Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W 60,61,72-75 ; (3) more diverse combinations of elements, such as VCoNi 76 , Co-Fe-Ni-Ti 74,77 , Al-Cr-Fe-Ni-Ti 78 , AlNbTiV 79 , AlHfNbTaTiZr and their subsystems 54 ; and (4) multication ceramics with rocksalt 80 and pyrochlore 81 structures. Despite the abundance of observations, however, details of how this mechanism impacts CCMs are still not fully clear.…”

“…The term 'K-state' originates from the German 'Komplexer Zustand' ('complex state'). Moreover, SRO often signals incipient ordering tendencies that may manifest at low temperature, for example, the precipitation of ordered phases in MoNbTaW 60 , AlNbTiV 79 , VCoNi 76 , Al-Cr-Fe-Ni-Ti 78,86 and Cr-Ta-Ti-V-W 73 .…”

Electrons Meet Alloy Development: A γ‐TiAl‐Based Alloy Showcase

“…With increasing O content, the ordering temperature significantly drops. Another recent example is the work of Körmann et al [ 73 ] They applied DFT to parameterize machine‐learned interatomic potentials (MLIPs) in a quaternary TiAlNbV high‐entropy alloy (HEA). Subsequently, they used those MLIPs to conduct Monte Carlo (MC) simulation, suggesting that the bcc HEA tends to order below into the phase with the B2 structure.…”