Temperature-dependent structural, mechanical, and thermodynamic properties of B2-phase Ti2AlNb for aerospace applications

Goyal, Kushagra; Bera, Chandan; Sardana, Neha

doi:10.1007/s10853-022-07788-3

Cited by 5 publications

(1 citation statement)

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“…Ti 2 AlNb alloys are regarded as the next generation of the most promising lightweight high-temperature aerospace structural materials due to their excellent mechanical properties, such as their good creep resistance, high strength-to-weight ratio, and satisfactory hot workability [1][2][3]. Ti 2 AlNb alloys are composed of an order of the orthorhombic (O) phase (space group: Cmcm, Pearson symbol: oS16), B2 phase (space group: Pm3m, Pearson symbol: cP2), and α 2 phase (space group: P6 3 /mmc, Pearson symbol: hP8) [4,5].…”

Section: Introductionmentioning

confidence: 99%

First-Principles Investigation on the Adsorption and Diffusion of Oxygen at the B2(110)–O(001) Interface in Ti2AlNb Alloys

Zhang,

Xiang,

et al. 2024

Metals

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The adsorption and diffusion of oxygen at the B2(110)[1¯11]||O(001)[11¯0] interface in Ti2AlNb alloys were investigated via first-principles calculations. Only a 2.6% interfacial mismatch indicates that B2(110)–O(001) is basically a stable coherent interface. The calculated adsorption energies and diffusion energy barriers show that oxygen prefers to occupy the Ti-rich interstitial sites, and once trapped, it hardly diffuses to other interstitial sites, thus promoting the preferential formation of Ti oxides. Under the premise of a Ti-rich environment, a Nb-rich environment is more favorable for oxygen adsorption than an Al-rich environment. The electronic structures suggest that O 2p orbitals mainly occupy the energy region below −5 eV, bonding with its coordinated atoms of Ti, Al, and Nb. However, Al 3p and Nb 4d orbitals near the Fermi level couple with sparsely distributed O 2p orbitals, forming anti-bonding, which is not conducive to oxygen adsorption. Because Nb 4d electrons are more localized than Al 3p electrons are, Nb–O anti-bonding is weaker. O–Ti has almost no contribution to anti-bonding, suggesting good bonding between them. This is consistent with the experimental observations that TiO2 is the main oxidation product.

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