“…Using the Thermo-calc software with the TTNI 8 database they found that MoNbTaTiW has a BCC structure at high temperatures, with an HCP phase appearing below 640 • C, although, as far as the authors are aware, this phase has not been reported experimentally. Bhandari et al [37] calculated the thermal expansion coefficient as a function of temperature of the equiatomic MoNbTaTiW alloy using density functional theory (DFT), on a 100-atom randomised supercell, and Debye theory, predicting a linear thermal expansion coefficient which rises steeply with temperature and plateaus at 550 K at 9 ×10 −6 K −1 [37]. In this work, we demonstrate that the temperature dependence of HEA thermal expansion coefficients can be predicted using computationally efficient special quasi-random structure (SQS) supercells and first-principles density functional perturbation theory.…”