JI Ru-yi1, ZHAO Yu-hong1, WEN Zhi-qin1, HAN Pei-de2
（1. School of Materials Science and Engineering, North University of China, Taiyuan 030051, China; 2. School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China）
Abstract： We employ density functional theory to study the mechanical, electronic and thermodynamic properties of the cubic NiTi in a prssure range of 0-40 GPa. The calculated lattice parameters are well in agreement with experimental values and other calculated results, showing that the B2 NiTi is mechanically stable and no phase transformation occurs with pressure going up to 40 GPa. The bulk modulus B, shear modulus G, Young’s modulus E and B/G of B2 NiTi improve linearly with increasing pressure, implying that the volume change resistance, shear deformation resistance and elastic stiffness could also be strengthened by pressure. The pressure could also have an influence on the ductility of NiTi. The density of state (DOS) of NiTi indicates that the bonding nature of B2 NiTi is metallic combining with covalent bonding, and pressure has no significant influence on the electronic properties in a pressure range of 0-40 GPa. In addition, the dependences of temperature and pressure on Debye temperature ΘD, heat capacity Cv and Cp are further studied to figure out the thermodynamic properties of B2 NiTi. All above are especially useful to further study the properties of NiTi.
Key words： B2 NiTi; mechanical properties; thermodynamics; first-principles
CLD number： TG146Document code： A
Article ID： 1674-8042（2017）02-0125-09 doi： 10.3969/j.issn.1674-8042-2017-02-004
References
［1］Wever D J, Veldhuizen A G, De V J, et al. Electrochemical and surface characterization of a nickel-titanium alloy. Biomaterials, 1998, 19(7/8/9)： 761.
［2］Dutta R S, Madangopal K, Gadiyar H S, et al. Biocompatibility of Ni-Ti shape memory alloy. British Corrosion Journal, 2013, 28(28)： 217-221.
［3］Thierry B, Tabrizian M, Trepanier C, et al. Effect of surface treatment and sterilization processes on the corrosion behavior of NiTi shape memory alloy. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2000, 51(4)： 685-93.
［4］XU Hui-bin, MENG Ling-jie, LI Yan. One kind of high temperature fibers of Ti-Ni-Al alloy： Chinese Patent, 200510053911.1. 2005-03-14.
［5］ZHAO Xin-qing, XU Hui-bin, LI Yan. One kind of high temperature fibers of Ti-Ni-Al-Mo alloy： Chinese Patent, 200510053910.7. 2005-03-14.
［6］LI Yan, XU Hui-bin, ZHAO Xin-qing. One kind of high temperature fibers of Ti-Ni-Al-Nb alloy： Chinese Patent, 200510053909.4. 2005-03-14.
［7］MENG Ling-jie, LI Yan, ZHAO Xin-qing, et al. Effect of Nb on strengthening mechanism of Ti-rich TiNiAl intermetallics. Hangkong Xuebao/acta Aeronautica Et Astronautica Sinica, 2007, 28(5)： 1206-1209.
［8］Huang H, Durand B, Sun Q P, et al. Experimental study of NiTi alloy under shear loading over a large range of strain rates. International Journal of Impact Engineering, 2017： 15-46.
［9］Shahmir H, Nili-Ahmadabadi M, Huang Y, et al. Shape memory effect in nanocrystalline NiTi alloy processed by high-pressure torsion. Materials Science & Engineering A, 2015, 626(626)： 203-206.
［10］Wagner F X, Windl W. Lattice stability, elastic constants and macroscopic moduli of NiTi martensites from first principles. Acta Materialia, 2008, 56(20)： 6232-6245.
［11］Heinen R, Hackl K, Windl W, et al. Microstructural evolution during multiaxial deformation of pseudoelastic NiTi studied by first-principles-based micromechanical modeling. Acta Materialia, 2009, 57(13)： 3856-3867.
［12］HU Cui-e, ZENG Zhao-yi, NIU Zheng-wei, et al. Dynamical stability of NiTi under high pressure and high temperature. Journal of Alloys & Compounds, 2014, 608(608)： 258-260.
［13］Segall M D, Lindan P J D, Probert M J, et al. First-principles simulation： ideas, illustrations and the CASTEP code. Journal of Physics： Condensed Matter, 2002, 14(11)： 2717.
［14］Perdew J P. Density functional approximation for the correlation energy of the inhomogeneous electron gas. Physical Review B Condensed Matter, 1986, 33(12)： 8822-8824.
［15］Laasonen K, Pasquarello A, Car R, et al. Car-Parrinello molecular dynamics with Vanderbilt ultrasoft pseudopotentials. Physical Review B Condensed Matter, 1993, 47(16)： 10142.
［16］Perdew J P, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Physical Review Letters, 1996, 78(18)： 3865.
［17］Fischer T H, Almlof J. General methods for geometry and wave function optimization. Journal of Physical Chemistry, 1992, 96(24)： 9768-9774.
［18］Vinet P, Ferrante J, Smith J R, et al. Equation of state with temperature effects for solids. Physical Review B, 1987, 35： 1945.
［19］Hultgren R, Desai P D, Hawkins D T, et al. Selected values of thermodynamic properties of the elements// Selected values of thermodynamic properties of metals and alloys. US： Wiley, 1973： 55-98.
［20］Sittner P, Lukás P, Neov D, et al. In situ neutron diffraction studies of martensitic transformations in NiTi. Journal of Physic IV, 2003, 112： 709-712.
［21］Mercier O, Melton K N, Gremaud G, et al. Single-crystal elastic constants of the equiatomic NiTi alloy near the martensitic transformation. Journal of Applied Physics, 1980, 51(3)： 1833-1834.
［22］Nye J F. Physical properties of crystals. Materials Today, 1985, 10(6)： 391-397.
［23］ZHAO Yu-hong, HOU Hua, ZHAO Yu-hui, et al. First-principles study of the nickel-silicon binary compounds under pressure. Journal of Alloys & Compounds, 2015, 640： 233-239.
［24］Hill R W. The elastic behavior of a crystalline aggregate. In: Proceedings of the Physical Society, 1952, 65(5)： 349.
［25］Pugh S F. XCII. Relations between the elastic moduli and the plastic properties of polycrystalline pure metals. Philosophical Magazine, 1954, 45(367)： 823-843.
［26］Vahldiek F W, Mersol S A. Anisotropy in single-crystal refractory compounds. US： Springer, 1968.
［27］Nye J F. Physical properties of crystals. Oxford： Clarendon Press, 1985.
［28］Blanco M A, Francisco E, Lua a V. GIBBS： isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Computer Physics Communications, 2004, 158(1)： 57-72.
［29］Otero-De-La-Roza A, Abbasi-Pérez D, Lua a V. GIBBS2： A new version of the quasiharmonic model code. II. Models for solid-state thermodynamics, features and implementation. Computer Physics Communications, 2011, 182(10)： 2232-2248.
第一性原理研究压力下NiTi合金B2相的结构、力学以及热力学性质
吉如意1， 赵宇宏1， 文志勤1， 韩培德2
（1. 中北大学 材料科学与工程学院， 山西 太原 030051； 2. 太原理工大学 材料科学与工程学院， 山西 太原 030024）
摘要： 运用第一性原理研究0~40 GPa下B2相NiTi合金的机械性能、 电子性质以及热力学性能。 计算发现， 几何优化后NiTi晶体的晶格常数与实验值和其他文献提供的数值大体一致， 表明随着压力的增加该型合金力学稳定且没有相变产生。 NiTi合金的体模量B、 剪切模量G和杨氏模量E以及B/G的值随压力增大呈线性增加， 表明压力使其抗体积变形能力、 抗剪变能力及塑性增强。 研究发现， 压力也会使NiTi合金的各向异性发生改变。 对NiTi合金态密度的研究表明， 该合金同时显现出共价性与离子性， 并且压力对其电子性质无明显影响。 此外， 本文还研究了不同温度和压力下NiTi合金的热力学性能， 包括德拜温度ΘD，热容Cv和Cp的变化， 为今后实验提供理论数据。
关键词： B2 NiTi； 力学性质； 热力学性质； 第一性原理
引用格式：JI Ru-yi, ZHAO Yu-hong, WEN Zhi-qin, et al. Study on structural, mechanical and thermodynamic properties of B2 NiTi under pressures based on first-principles. Journal of Measurement Science and Instrumentation, 2017, 8（2）： 125-133. ［doi： 10.3969／j.issn.1674-8042.2017-02-004］
[full text view]
