In recent years, Ti-Al alloys have attracted significant attention in the field of alloy materials science due to their favorable properties, which include low density, high specific strength and elasticity modulus, good creep and oxidation resistance, as well as low manufacturing costs. However, due to limitations of experimental techniques, the influence of Ti doping concentration on the properties of Ti-Al alloys and the underlying physical mechanisms remain incompletely understood. In this paper, first-principles calculations based on quantum mechanics and density functional theory, combined with the virtual crystal approximation and the quasi-harmonic Debye model, are used to simulate the thermodynamic and mechanical properties of Ti-Al alloys as a function of Ti concentration. The effects of Ti doping on the equation of state, bulk modulus, thermal expansion coefficient, and heat capacity under different pressures and temperatures, are systematically investigated, and the physical origins of these changes are discussed. The results show that under high temperature and pressure, Ti doping reduces in volume and thermal expansion coefficient of Ti-Al alloys compared with pure Al, while increasing the bulk modulus and specific heat capacity. The most significant effects occurring within a Ti doping range up to 15%, indicating an optimal doping ratio for the thermal properties examined in this work. These findings establish a bridge between the micro-structure and macroscopic physical properties of Ti-Al alloys, providing theoretical support for their engineering applications.Moreover, they provide insight into the micro‑physical origins of concentration‑dependent thermodynamic behavior in alloys, which can serve as a theoretical reference for the design of novel alloy systems.
KawabtaT, TamuraT, IzumiO.Effect of Ti/Al ration and Cr, Nb and hf addition on material factor and mechanical properties in TiAl [J].Metall Trans A, 1993, 24(1): 141-150.
[2]
HuangS C, HallE L.Synthesis, properties and applications of titanium aluminides [C]//Lacombe P, Tricot R, Beranger G.Proceedings of the 6th World Conference on Titanium. Cannes, France: Society of France Metallurgy, 1988: 1109-1114.
[3]
HuangS C, HallE L.Characterization of the effect of vanadium additions to TiAI base alloy [J].Acta Metallurgica et Materialia, 1991, 39(6): 1053-1060.
[4]
GeG, WangZ, ZhangL, et al.Hot deformation behavior and artificial neural network modeling of β-γ TiAl alloy containing high content of Nb [J].Mater Today Commun, 2021, 27: 102405.
[5]
OomoriT, YoneyamaT, OikawaH.High-temperature deformation behavior of alpha Ti-5.6 mol%Al alloy [J].Transactions of the Japan Institute of Metals, 1988, 29(5): 399-405.
[6]
WangZ T, ZhengG, QiZ X, et al. Structures, microstructures, properties, and applications of TiAl alloys [J]. Chinese Science Bulletin, 2023, 68(25): 3259-3274.
MarkA, DidierD F, MarkV S, et al.First-principles phase-stability study of fcc alloys in the Ti-Al system [J].Phys Rev B, 1992, 46(9): 5055-5071.
[9]
ChubbS R, PaconstantopoulosD A, KleinB M.First-principles study of L10 Ti-Al and V-Al alloys [J].Phys Rev B, 1988, 38(17): 12120-12124.
[10]
MorinagaM, SaitoJ, YukawaN, et al.Electronic effect on the ductility of alloyed TiAl compound [J].Acta Metallurgica et Materialia, 1990, 38(1): 25-29.
[11]
TaoH J, PengK, XieY Q, et al.Research advance on brittleness of Ti-Al intermetallics [J].Materials Science and Engineering of Powder Metallurgy, 2007, 12(6): 330-336.
HobenbergP, KohnW. Inhomogeneous electron gas [J].Phys Rev, 1964, 136(3B): B864-B871.
[14]
KohnW, ShamL J. Self-consistent equations including exchange and correlation effects [J].Phys Rev, 1965, 140(4A): A1133-A1138.
[15]
PayneM C, TeterM P, AllenD C, et al. Iterative minimization techniques for ab initio total-energy calculations: Molecular dynamics and conjugate gradients [J].Rev Mod Phys, 1992, 64(4):1045-1097.
[16]
MilmanV, WinklerB, WhiteJ A, et al. Electronic structure, properties, and phase stability of inorganic crystals: A pseudopotential plane-wave study[J].Int J Quantum Chem, 2000, 77(5): 895-910.
BlancoM A, FranciscoE, LuañaV.GIBBS:Isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model [J].Comput Phys Commun, 2004, 158(1): 57-72.
[21]
HuangA, LuZ P, ZhouM, et al.Effects of the doping of Al and O interstitial atoms on thermodynamic properties of α-Al2O3: First-principles calculations [J].Acta Phys Sin, 2017, 66(1): 016103.
ZhouM, TaoY Q, ZhouX Y, et al.First-principles study on state equation and thermodynamic properties of energetic ionic salt TKX-50 [J].Chinese Journal of Computational Physics, 2024, 41(4): 487-493.
YuanW L, YaoB X, LiX, et al. First principles study on structural stability, mechanical, and thermodynamic properties of γ'-Co3 (V, M) (M=Ti, Ta) phase [J].Acta Phys Sin, 2024, 73(8): 086104.
YangJ J, LuL Y. First principles calculations of structural and thermodynamic properties of half-Heusler alloy LiMgAs [J].J Sichuan Univ(Nat Sci Ed), 2023, 60(2): 024001.