Modified embedded-atom method potential for high-temperature crystal-melt properties of Ti–Ni alloys and its application to phase field simulation of solidification

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.

Modified Embedded‐Atom Method Potentials for the Plasticity and Fracture Behaviors of Unary HCP Metals

“…In addition, the Zhou [ 22 ] and Ackland [ 30 ] potentials underestimate the unstable stacking fault energy on the basal and pyramidal I planes (Figure 4c,e), leading to lower shear strengths. Further comparisons with other potentials [ 32–46 ] show that the new potential here also provides better overall accuracies (Figures S8–S11, Supporting Information).…”

Phase-field modeling of microstructure evolution: Recent applications, perspectives and challenges

“…The interface energies between matrix and precipitates for different crystallographic orientations can be computed using density functional theory [78][79][80][81][82][87][88][89][90][91], and grain boundary energy and mobility can be determined by means of MD simulations [134][135][136]. For solidification, MD simulations can also be used to determine the solid-liquid interface energy [252,261,262,[305][306][307][308][309][310] as well as its kinetic coefficient [253,305,[311][312][313][314][315][316]. However, for such simulations to be predictive, one must pay special attention to selecting interatomic potentials that remain accurate up to the melting temperature (see e.g.…”

“…However, for such simulations to be predictive, one must pay special attention to selecting interatomic potentials that remain accurate up to the melting temperature (see e.g. [307][308][309][310]).…”

Bayesian Data Assimilation of Temperature Dependence of Solid–Liquid Interfacial Properties of Nickel

“…Therefore, various molecular dynamics (MD) simulations have contributed to the estimation of solid–liquid interfacial energy and mobility [ 16 , 17 , 18 , 19 , 20 , 21 ]. The capillary fluctuation method (CFM) [ 18 , 19 ] is the most popular technique for estimation of solid–liquid interfacial energy, including its anisotropy, and this technique has been applied to various metals and alloys [ 22 , 23 , 24 , 25 , 26 ]. Moreover, classical nucleation theory (CNT)-based techniques are often employed to estimate the solid–liquid interfacial energy [ 20 , 27 , 28 ].…”