Elastic and thermodynamic properties of the Ti₂AlNb orthorhombic phase from first‐principles calculations

Abstract

Ti2AlNb‐based alloy with a dominated orthorhombic phase is one of the most promising high‐temperature structural materials. In this work, the equilibrium volume, elastic, and thermodynamic properties of the ordered O phase with stoichiometric Ti2AlNb were predicted under different temperatures using first‐principles calculations based on density functional theory combined with quasi‐harmonic approximation (QHA). With the increase of temperature from 0 to 1300 K, the elastic properties decrease moderately and the bonding strength weakens slightly. The intrinsic properties of the Ti2AlNb O phase are ductile at all temperature considered. In order to explore the evolution mechanism of the temperature‐dependent elastic properties further, the density of state (DOS) has been analyzed. The stoichiometric Ti2AlNb O phase shows good high‐temperature mechanical and thermal stability, which is a kind of potential high‐temperature alloy applied in aeronautics industries.

Theoretical study of the effects of alloying elements on TiO2/Ti2AlNb interface adhesion properties

“…31 (The PBE functional has been proven to be more accurate in first-principles calculation studies of Ti 2 AlNb and γ-TiAl systems as shown in ref. 24, 32 and 33.) Projector augmented wave (PAW) pseudopotentials are used in the present study.…”

Effect of Volume Fraction of Reinforcement on Microstructure and Mechanical Properties of In Situ (Ti, Nb)B/Ti2AlNb Composites with Tailored Three-Dimensional Network Architecture

“…The O phase possesses improved ductility when compared to the α 2 phase since the <2c+a> slip system can be activated due to the low critical shear stress for slip activation [37,44]. The elasticity moduli of O, B2, α 2 and (Ti, Nb)B are 148.0 [45], 132.2 [30], 151.7 [46,47] and 453 GPa [30], respectively. The stiffness of the PPBs area, which is full of α 2 and (Ti, Nb)B phases, is higher than the matrix area, resulting in the stress concentration of the PPBs area during the tensile process.…”

First-Principles Calculations on Structural Property and Anisotropic Elasticity of γ1-Ti4Nb3Al9 under Pressure

“…Although the ground-state elastic properties of some constituent phases in high-Nb containing TiAl alloys have already been investigated in both theory and experiment [13,14,15,16,17,18,19,20,21,22], the elastic properties of various phases under pressure have rarely been studied. Up to now, the structural and elastic properties of $\gamma$-TiAl, ${\alpha }_2$-Ti${}_3$Al and B19-TiAl phases under pressure have been investigated by using first-principles calculations [23,24,25,26].…”