Accurate prediction of high-temperature elastic constants of Ti0.5Al0.5N random alloy

Temperature-dependent elastic properties of binary and multicomponent high-entropy refractory carbides

“…Despite this, the elastic constants of these refractory ceramics have been primarily evaluated at 0 K. Ab initio estimations of elastic constants at finite temperatures are often done using static calculations at cell volumes determined in the quasiharmonic approximation for the thermal expansion (see, e.g., [23][24][25][26][27]). However, explicit inclusion of lattice vibrations in theoretical modeling is shown to result in significant differences in second-order elastic moduli and a change of elastic anisotropy of materials at moderate or high temperatures [28,29]. Ab initio molecular dynamics (AIMD) simulations, which inherently reproduce anharmonic vibrational effects, provide more reliable predictions of elastic constants at elevated temperature [29][30][31].…”

“…However, explicit inclusion of lattice vibrations in theoretical modeling is shown to result in significant differences in second-order elastic moduli and a change of elastic anisotropy of materials at moderate or high temperatures [28,29]. Ab initio molecular dynamics (AIMD) simulations, which inherently reproduce anharmonic vibrational effects, provide more reliable predictions of elastic constants at elevated temperature [29][30][31].…”

“…Recently, we have reported on an ab initio molecular dynamics (AIMD) approach for computing stress/strain curves of single-crystal B1 ceramics subject to tensile and shear deformation at any temperature of interest [32][33][34]. The simulations employ deformations well beyond the elastic limit conventionally used to calculate the elastic constants [28][29][30][31], and allow evaluating mechanical properties including, e.g., ideal strengths, moduli of resilience, toughness, and elongation at fracture. The method detailed in Refs.…”

Combining ab‐initio and machine learning techniques for theoretical simulations of hard nitrides at extreme conditions

“…Although cubic Ti 1−x Al x N systems have historically been modelled successfully using the PBE GGA approach for the exchange-correlation potential [96,97], making the assumption that the same will hold for the Al-rich phases of both B1 and B4 Ti 1−x Al x N anything but certain, given their semiconducting nature. On the contrary, studies about Ti impurities in w-AlN commonly make use of higher order functionals to accurately model the Ti 3d electrons [98,99,100].…”

HADB: A materials-property database for hard-coating alloys

“…The thermal expansion of quaternary nitrides has been predicted by a quasi-harmonic Debye model with a piece-wise linear interpolation of the ab-initio elastic constants calculated at 0 K only for binary materials and 50-50 ternary alloys [20]. High-temperature thermodynamics and elastic constants of Ti 1−𝑥 Al 𝑥 N alloys have been investigated using different molecular dynamics approaches [21][22][23]. It has been underlined that with machine learned interatomic potentials one can efficiently and accurately predict the elastic moduli of Ti 0.5 Al 0.5 N [24].…”