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Citation: H. Tang, Y. Zhang, Q. Li, H. Xu, Y. Wang, Y. Wang, and J. Li (2022), "High accuracy neural network interatomic potential for NiTi shape memory alloy", Acta Materialia, 118217. DOI: 10.1016/j.actamat.2022.118217.
Abstract: Nickel-titanium (NiTi) shape memory alloys (SMA) are widely used, however simulating the martensitic transformation of NiTi from first principles remains challenging. In this work, we developed a neural network interatomic potential (NNIP) for near-equiatomic Ni-Ti system through active-learning based acquisitions of density functional theory (DFT) training data, which achieves state-of-the-art accuracy. Phonon dispersion and potential-of-mean-force calculations of the temperature-dependent free energy have been carried out. This NNIP predicts temperature-induced, stress-induced, and deformation twinning-induced martensitic transformations from atomic simulations, in significant agreement with experiments. The NNIP can directly simulate the superelasticity of NiTi nanowires, providing a tool to guide their design.

Notes: This is an alternate parameterization of the potential listed in the paper. The developers note that "although v2 appears better for more general scenarios according to our tests, there are still a few cases where v1 is more accurate". This potential was designed for equiatomic NiTi shape memory alloy and can be used for NiTi alloy with slight off-stoichiometry. The potential should not be used for pure Ni, pure Ti, or Ni-Ti alloy far from the equiatomic composition.

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Notes: These files were provided by Hao Tang on August 3, 2022. Detailed instructions on using this potential in MD simulations can be found at the link below. We suggest users compress the model (see the documentation) before using it for MD simulation, as this will make the calculation significantly faster with limited influence on accuracy.
File(s): Link(s):
Citation: H. Tang, Y. Zhang, Q. Li, H. Xu, Y. Wang, Y. Wang, and J. Li (2022), "High accuracy neural network interatomic potential for NiTi shape memory alloy", Acta Materialia, 118217. DOI: 10.1016/j.actamat.2022.118217.
Abstract: Nickel-titanium (NiTi) shape memory alloys (SMA) are widely used, however simulating the martensitic transformation of NiTi from first principles remains challenging. In this work, we developed a neural network interatomic potential (NNIP) for near-equiatomic Ni-Ti system through active-learning based acquisitions of density functional theory (DFT) training data, which achieves state-of-the-art accuracy. Phonon dispersion and potential-of-mean-force calculations of the temperature-dependent free energy have been carried out. This NNIP predicts temperature-induced, stress-induced, and deformation twinning-induced martensitic transformations from atomic simulations, in significant agreement with experiments. The NNIP can directly simulate the superelasticity of NiTi nanowires, providing a tool to guide their design.

Notes: This is the parameterization of the potential as used by the associated publication. This potential was designed for equiatomic NiTi shape memory alloy and can be used for NiTi alloy with slight off-stoichiometry. The potential should not be used for pure Ni, pure Ti, or Ni-Ti alloy far from the equiatomic composition.

See Computed Properties
Notes: These files were provided by Hao Tang on August 3, 2022. Detailed instructions on using this potential in MD simulations can be found at the link below. We suggest users compress the model (see the documentation) before using it for MD simulation, as this will make the calculation significantly faster with limited influence on accuracy.
File(s): Link(s):
Citation: S. Kavousi, B.R. Novak, M.I. Baskes, M. Asle Zaeem, and D. Moldovan (2019), "Modified embedded-atom method potential for high-temperature crystal-melt properties of Ti–Ni alloys and its application to phase field simulation of solidification", Modelling and Simulation in Materials Science and Engineering, 28(1), 015006. DOI: 10.1088/1361-651x/ab580c.
Abstract: We developed new interatomic potentials, based on the second nearest-neighbor modified embedded-atom method (2NN-MEAM) formalism, for Ti, Ni, and the binary Ti–Ni system. These potentials were fit to melting points, latent heats, the binary phase diagrams for the Ti rich and Ni rich regions, and the liquid phase enthalpy of mixing for binary alloys, therefore they are particularly suited for calculations of crystal-melt (CM) interface thermodynamic and transport properties. The accuracy of the potentials for pure Ti and pure Ni were tested against both 0 K and high temperature properties by comparing various properties obtained from experiments or density functional theory calculations including structural properties, elastic constants, point-defect properties, surface energies, temperatures and enthalpies of phase transformations, and diffusivity and viscosity in the liquid phase. The fitted binary potential for Ti–Ni was also tested against various non-fitted properties at 0 K and high temperatures including lattice parameters, formation energies of different intermetallic compounds, and the temperature dependence of liquid density at various concentrations. The CM interfacial free energies obtained from simulations, based on the newly developed Ti–Ni potential, show that the bcc alloys tend to have smaller anisotropy compared with fcc alloys which is consistent with the finding from the previous studies comparing single component bcc and fcc materials. Moreover, the interfacial free energy and its anisotropy for Ti-2 atom% Ni were also used to parameterize a 2D phase field (PF) model utilized in solidification simulations. The PF simulation predictions of microstructure development during solidification are in good agreement with a geometric model for dendrite primary arm spacing.

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Notes: This file was sent by Sepideh Kavousi (Colorado School of Mines) on 10 Nov. 2020 and posted with her permission.
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Citation: Y.-K. Kim, H.-K. Kim, W.-S. Jung, and B.-J. Lee (2017), "Development and application of Ni-Ti and Ni-Al-Ti 2NN-MEAM interatomic potentials for Ni-base superalloys", Computational Materials Science, 139, 225-233. DOI: 10.1016/j.commatsci.2017.08.002.
Abstract: Interatomic potentials for the Ni-Ti and Ni-Al-Ti systems have been developed based on the second nearest-neighbor modified embedded-atom method (2NN-MEAM) formalism. The Ni-Ti binary potential reproduces fundamental materials properties (structural, elastic, thermodynamic, and thermal stability) of alloy systems in reasonable agreement with experiments, first-principles calculations and thermodynamic calculations. Atomistic simulations using the Ni-Al-Ti ternary potential validate that the potential can be applied successfully to atomic-scale investigations to clarify the effects of titanium on important materials phenomena (site preference in γ', γ-γ' phase transition, and segregation on grain boundaries) in Ni-Al-Ti ternary superalloys.

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Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020.
File(s):
Citation: W.-S. Ko, B. Grabowski, and J. Neugebauer (2015), "Development and application of a Ni-Ti interatomic potential with high predictive accuracy of the martensitic phase transition", Physical Review B, 92(13), 134107. DOI: 10.1103/physrevb.92.134107.
Abstract: Phase transitions in nickel-titanium shape-memory alloys are investigated by means of atomistic simulations. A second nearest-neighbor modified embedded-atom method interatomic potential for the binary nickel-titanium system is determined by improving the unary descriptions of pure nickel and pure titanium, especially regarding the physical properties at finite temperatures. The resulting potential reproduces accurately the hexagonal-close-packed to body-centered-cubic phase transition in Ti and the martensitic B2−B19′ transformation in equiatomic NiTi. Subsequent large-scale molecular-dynamics simulations validate that the developed potential can be successfully applied for studies on temperature- and stress-induced martensitic phase transitions related to core applications of shape-memory alloys. A simulation of the temperature-induced phase transition provides insights into the effect of sizes and constraints on the formation of nanotwinned martensite structures with multiple domains. A simulation of the stress-induced phase transition of a nanosized pillar indicates a full recovery of the initial structure after the loading and unloading processes, illustrating a superelastic behavior of the target system.

LAMMPS pair_style meam (2015--Ko-W-S--Ni-Ti--LAMMPS--ipr2)
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Notes: These files were sent by Won-Seok Ko (University of Ulsan, South Korea) on 24 July 2016 and posted with his permission.
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Date Created: October 5, 2010 | Last updated: December 14, 2023