Modified Embedded Atom Method Research Articles

Phase stability and mechanical property of gallium-stabilized <x content-type="symbol">δ</x>-plutonium

Plutonium (Pu) is a very important nuclear material, acting as a key fissile component in nuclear weapons as well as in the uranium Pu mixed oxide fuel. The existence of six equilibrium solid phases at ambient pressure in its phase diagram makes Pu one of the most complex elements in the Periodic Table. The phase stability and mechanical properties play key roles in its application in nuclear industry. As a radioactive element, Pu is vulnerable to aging, decaying to uranium by emitting an α particle. This process eventually results in abundant crystal defects and helium bubbles. To maintain the effectiveness of Pu-based materials in practical applications, it is necessary to study the mechanical and structural properties of Pu. However, it is challenging to obtain the atomistic mechanism of the evolution of Pu-based materials in experimental studies due to the limitations of spatial and temporal resolution ratio. Recently, numerical simulation especially classical molecular dynamics simulation has become an important tool to study the basic properties of materials at nanoscale. The two phases of greatest interest are the monoclinic α -phase, which is the basic form of unalloyed Pu at room temperature, and the face-centered-cubic (FCC) δ -phase, which can be stabilized to room temperature by alloying with a few atomic percent (at.%) of aluminum (Al) or gallium (Ga). In this work, a molecular dynamics simulation model is set up to investigate the phase stability of Ga-stabilized FCC phase Pu ( δ -Pu). A widely accepted modified embedded atom model (MEAM) potentials are implemented to describe the interactions of the binary system using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The results indicate that unalloyed Pu deviates substantially from a typical FCC structure with lattice distortion and domain decomposition at room temperature and ambient pressure, while it is much more stable at 700 K. Furthermore, it is found that doping Ga can remarkably improve the phase stability of Pu at room temperature, and the stability increases with the atomic percent of Ga in Pu-Ga alloy. Energetically, the average potential energy per atom and the total potential energy decreases obviously with increasing the atomic percentage of Ga in the alloy. Based on the stability results above, we study the elastic property of Ga-stabilized δ -Pu alloy. According to our simulation results, δ -Pu is highly anisotropic with a Zener Index of 6.89, a much higher value than those of other metals with FCC structure such as copper, aluminum and gold. In addition, we perform uniaxial tension on single crystal nanowires with different crystallographic orientations and transverse directions. The elastic moduli of the typical low index crystal orientations [100], [110] and [111] are calculated to be 12.86, 33.47 and 74.37 GPa, respectively. Our simulation results reveal that increasing the concentration of Ga can decrease the anisotropy but increase the elastic moduli conversely, which is in good agreement with available experimental data for non-aged Ga stabilized polycrystalline δ -Pu. It is expected that our findings could lead to an improvement of fundamental understanding of the phase stability and anisotropy in Pu-Ga alloy, which is of great significance to understand the self-radiation effects and aging mechanisms of Pu-based nuclear materials.

Numerical Investigation on Atomic Migration Effect on Thermal Conductivity of Al/Cu Interface Structures in Electronic Interconnection Packaging

At present, MEMS and micro/nano electronic packaging technology have an exhaustive range of applications in the field of mass-produced commercial products, such as cell phones, computer, automobiles, and pedometers, which cause a strong demand for the reliability of heat transfer in nano or micro scales. Wire bonding process has been widely used in the MEMS or devices packaging approach to create high aspect interconnection structures [1], hence, the thermal analysis, thermal design, and thermal management become more and more important for microelectronic system or microelectronic devices. The interfacial structures of dissimilar materials are suffering the high stress gradients due to the thermal and stiffness mismatches of the different materials [2, 3]. The interface structures of dissimilar materials are very prone to crack initiations under the heat flow effect. The heat transfer across the interface is a critical consideration for the thermal design in the IC or devices manufacturing. Here we reveal the relationship between the atomic migration and thermal conductivity of Al/Cu interface in nanoscale heat transfer by using non-equilibrium molecular dynamics method. To create the Al/Cu interface, the modified Embedded-atom method (EAM) for alloy is used to describe the interatomic interactions between Cu/Cu, and Al/Cu interface. The results show that the interfacial diffusion is enhanced with the increase of the temperature from 400K-600K. The thermal conductivity of the Al/Cu interface, first increases, and then decreases. When the temperature is over 600K, it reaches the recrystallization temperature of Al. which makes to Al atoms recrystallization. The recrystallization of Al atoms may reduce the heat transfer efficiency of the Al/Cu diffusion region. That is to say, it reduces the thermal conductivity of Al/Cu interface when the temperature is over 600K. This means that we can enhance the interfacial heat transfer efficiency of Al/Cu interface and the cooling efficiency of IC by heat treatment in advance on interface structures. This investigation is helpful for understanding the interfacial heat transfer mechanism of the interface structures in the IC, which is helpful for the design of the interface in micro/nano manufacturing and benefit for the estimate the reliability of the IC manufacturing. Figure 1

Vibrational properties of vacancy in Au using modified embedded atom method potentials

Much improved result for lattice dynamics of Au is obtained with the use of modified embedded atom method (MEAM) potentials compared to the earlier embedded atom method (EAM) potentials. The MEAM potentials along with experimental phonons are utilised to calculate local spectra of neighbours of vacancy using Green's function method. The local spectrum of first neighbour of vacancy shows general loss of modes at lower frequencies with a resonance like sharp peak near the top end of the spectrum. The spectrum of second neighbour shows small changes from the host spectra except a pronounced dip in the middle. In accordance with the obtained features of local spectra of neighbours the calculated mean-square displacements are lower for both first and second neighbours as compared to that of host atoms. The calculated formation entropy is in reasonable agreement with other calculations and available experimental values.

Molecular dynamics simulations of plasticity and cracking in lithiated silicon electrodes

First-principle calculations have provided critical insights into the deformation behavior of lithiated silicon electrodes in high-capacity lithium ion batteries, but quantitative interpretations have been limited by the size scales of these calculations. Here, we show that large-scale molecular dynamics (MD) simulations, based on the modified embedded atom method (MEAM) potential, are capable of describing the elastic softening and plastic behavior of LixSi alloys. In particular, our MD simulations at 0 K correctly reproduce the stress–strain response of LixSi alloys from Density Functional Theory (DFT) calculations across all Li concentrations, while matching the corresponding yield strength data from existing experiments at 300 K. Results from these MD simulations reveal a sharp transition in the atomic-scale plasticity mechanisms for LixSi with increasing Li content: from the breaking of Li–Si bonds at x<1, to the breaking of Li–Li bonds at x>1. The associated transition in the fracture behavior from brittle to ductile is due to the high stretchability of Li–Li bonds compared to Li–Si and Si–Si bonds.

The anisotropy of hexagonal close-packed and liquid interface free energy using molecular dynamics simulations based on modified embedded-atom method

This work aims to comprehensively study the anisotropy of the hexagonal close-packed (HCP)-liquid interface free energy using molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM). As a case study, all the simulations are performed for Magnesium (Mg). The solid–liquid coexisting approach is used to accurately calculate the melting point and melting properties. Then, the capillary fluctuation method (CFM) is used to determine the HCP-liquid interface free energy (γ) and anisotropy parameters. In CFM, a continuous order parameter is employed to accurately locate the HCP-liquid interface location, and the HCP symmetry-adapted spherical harmonics are used to expand γ in terms of its anisotropy parameters (ε20, ε40, ε60 and ε66). Eight slip and twinning planes (basal, two prismatic, two pyramidal, and three twinning planes) are considered as the HCP-liquid interface planes. An average HCP-liquid interface free energy of 122.2 (mJ/m2), non-zero ε20, ε40, and ε66 parameters, and approximately zero ε60 parameter for Mg are predicted. Using these findings, the first preferred dendrite growth direction in solidification of Mg is predicted as [112¯0], which is in agreement with experiments. Also, a second preferred dendrite growth direction for Mg is predicted as [336¯2].

Interaction between oxygen interstitials and deformation twins in alpha-titanium

Twinning is an important deformation mechanism in many hexagonal close packed metals, including α-titanium (Ti) alloys. However, the mechanisms for twin nucleation, growth, and interaction with other defects are not completely understood. In this study we interrogate the behavior of oxygen (O) interstitials near a (101¯2) twin boundary using a combination of density functional theory (DFT) and modified embedded atom method (MEAM) calculations. The presence of the twin boundary significantly affects both interstitial formation energy as well as the activation barriers for diffusion between sites. We demonstrate that a tetrahedral interstitial is stable in the twin boundary, despite being unstable in bulk Ti, while the formation energies of the octahedral, hexahedral, and crowdion interstitials are all modified by a nearby twin. Further, the activation barriers for diffusion in the region near the twin are uniformly lower than in the bulk. An atom diffusing across the twin boundary moves through several paths with peak energies more than 0.3 eV lower than for comparable diffusion far from the twin, suggesting that the (101¯2) twin is a fast diffusion pathway and movement of oxygen interstitials across the twin during twin growth is possible.

Size-Dependent Surface Energy Density of Spherical Face-Centered-Cubic Metallic Nanoparticles.

The surface energy density of nano-sized elements exhibits a significantly size-dependent behavior. Spherical nanoparticle, as an important element in nano-devices and nano-composites, has attracted many interesting studies on size effect, most of which are molecular dynamics (MD) simulations. However, the existing MD calculations yield two opposite size-dependent trends of surface energy density of nanoparticles. In order to clarify such a real underlying problem, atomistic calculations are carried out in the present paper for various spherical face-centered-cubic (fcc) metallic nanoparticles. Both the embedded atom method (EAM) potential and the modified embedded atom method (MEAM) one are adopted. It is found that the size-dependent trend of surface energy density of nanoparticles is not governed by the chosen potential function or variation trend of surface energy, but by the defined radius of spherical nanoparticles in MD models. The finding in the present paper should be helpful for further theoretical studies on surface/interface effect of nanoparticles and nanoparticle-reinforced composites.

Atomistic modeling of high temperature uranium–zirconium alloy structure and thermodynamics

A semi-empirical Modified Embedded Atom Method (MEAM) potential is developed for application to the high temperature body-centered-cubic uranium–zirconium alloy (γ-U–Zr) phase and employed with molecular dynamics (MD) simulations to investigate the high temperature thermo-physical properties of U–Zr alloys. Uranium-rich U–Zr alloys (e.g. U–10Zr) have been tested and qualified for use as metallic nuclear fuel in U.S. fast reactors such as the Integral Fast Reactor and the Experimental Breeder Reactors, and are a common sub-system of ternary metallic alloys like U–Pu–Zr and U–Zr–Nb. The potential was constructed to ensure that basic properties (e.g., elastic constants, bulk modulus, and formation energies) were in agreement with first principles calculations and experimental results. After which, slight adjustments were made to the potential to fit the known thermal properties and thermodynamics of the system. The potentials successfully reproduce the experimental melting point, enthalpy of fusion, volume change upon melting, thermal expansion, and the heat capacity of pure U and Zr. Simulations of the U–Zr system are found to be in good agreement with experimental thermal expansion values, Vegard's law for the lattice constants, and the experimental enthalpy of mixing. This is the first simulation to reproduce the experimental thermodynamics of the high temperature γ-U–Zr metallic alloy system. The MEAM potential is then used to explore thermodynamics properties of the high temperature U–Zr system including the constant volume heat capacity, isothermal compressibility, adiabatic index, and the Grüneisen parameters.

Simulations of tensile bond rupture in single alkane molecules using reactive interatomic potentials

Molecular simulations were performed to study the energetics and geometries of bond rupture in single alkane molecules using three reactive hydrocarbon potentials: (1) modified embedded-atom method (MEAM) for saturated hydrocarbons, (2) ReaxFF, and (3) second-generation REBO. The total energy/force versus strain, strain at fracture, and strain energy release were compared for a homologous series of normal alkanes (ethane to undecane) with generalization to polyethylene. The CC bond distances and CCC bond angles were quantified, and a fragment analysis was performed. Overall, the MEAM and ReaxFF potentials are in reasonable agreement with first-principles data with MEAM matching DFT-calculated lowest energy fragments.

Examination of Solid-Solution Phase Formation Rules for High Entropy Alloys from Atomistic Monte Carlo Simulations

In this study, we used atomistic simulation methods to examine solid-solution phase formation rules for CoCrFeNi high entropy alloy. Using the Monte Carlo simulations based on the modified embedded atom method (MEAM) potentials, we sampled the thermodynamically equilibrium structures of the CoCrFeNi alloy and further predicted that the CoCrFeNi alloy could form a solid solution phase with high configurational entropy of 1.329R at 1373 K. Furthermore, we examined the stability of this solid solution phase of the CoCrFeNi alloy against the well-recognized solid-solution phase formation rules by varying the MEAM potentials and thus tuning the atom size and mixing enthalpy in the alloy. Our simulation results revealed that it required atom size difference effect $$ \left| \delta \right| < 0.05 $$ and mixing enthalpy effect −10 kJ/mol < ΔH ≈ 0 kJ/mol for the modeled CoCrFeNi alloy to remain a single solid solution phase.

Dynamical and transport properties of liquid gallium at high pressures.

Quantum molecular dynamics (QMD) simulations are used to calculate the equation of state, structure, and transport properties of liquid gallium along the principal shock Hugoniot. The calculated Hugoniot is in very good agreement with experimental data up to a pressure of 150 GPa as well as with our earlier classical molecular dynamics calculations using a modified embedded atom method (MEAM) potential. The self-diffusion and viscosity calculated using QMD agree with experimental measurements better than the MEAM results, which we attribute to capturing the complexity of the electronic structure at elevated temperatures. Calculations of the DC conductivity were performed around the Hugoniot. Above a density of 7.5 g/cm(3), the temperature increases rapidly along the Hugoniot, and the optical conductivity decreases, indicating simple liquid metal behavior.

Equilibrium segregation patterns and alloying in Cu/Ni nanoparticles: Experiments versus modeling

We analyze the segregation behavior of bimetallic nanoparticles (NPs) with moderate miscibility gap by applying a combined experimental/simulation approach to Cu/Ni as a model system. Using a hybrid molecular dynamics/Metropolis Monte Carlo algorithm (MD/MMC) based on the embedded atom method (EAM), we derive the equilibrium distribution of atomic species in the clusters for varying concentrations and particle structures. To cross-check the predictive power of our approach, we compare these results with modified EAM (MEAM) and density functional theory based ab initio calculations. This permits to identify possible shortcomings of the EAM when used to describe bimetallic NPs. Additionally, we isolate vibrational entropy contributions to the free energy of the NPs and special focus is put on the possibility of entropic stabilization of segregated versus solid solution NPs. Finally, we complement our simulations by experimental results, which are obtained by studying the behavior of plasma gas condensation synthesized Ni@Cu core-shell (CS) particles upon annealing.

MEAMfit: A reference-free modified embedded atom method (RF-MEAM) energy and force-fitting code

Ab initio modeling of materials has become routine in recent years, largely due to the success of density functional theory (DFT). However, for many processes in materials, realism is achieved only when millions of atoms are considered. Currently, such large scale simulations are beyond ab initio capabilities so that one has to resort to effective interatomic potentials that well represent ab initio data on smaller scales. Two of the more widely used types of interatomic potentials are embedded atom method (EAM) and modified embedded atom method (MEAM) potentials. Here we present a code that can use ab initio generated energies and forces to obtain representative EAM and reference-free MEAM type effective interatomic potentials. We illustrate the use of this code with ab initio computed thermal excitations in ZrC. Program summaryProgram title: MEAMfitCatalogue identifier: AEWY_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEWY_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 4467841No. of bytes in distributed program, including test data, etc.: 56403685Distribution format: tar.gzProgramming language: Fortran.Computer: Linux based workstations.Operating system: Linux.RAM: 120 MegabytesClassification: 16.1.External routines: TOMS611 Unconstrained Minimization [1] included in the MEAMfit code.Nature of problem: Fitting embedded atom method (EAM) and reference-free modified embedded atom method (RF-MEAM) potentials [2-3] to energies and forces produced by VASP [4-7].Solution method: A computer program is presented which uses a conjugate-gradient minimizer paired with a genetic algorithm to fit EAM and RF-MEAM potentials to energies and/or atomic forces read directly from VASP output files. Potentials produced by the code are directly usable with the LAMMPS [8] or Camelion [9] molecular-dynamics packages.Additional comments: User manual provided.!!!!! The distribution file for this program is over 56 Mbytes and therefore is not delivered directly when download or Email is requested. Instead a html file giving details of how the program can be obtained is sent. !!!!!Running time: The run-time depends on the required level of accuracy of the final potential. For an EAM potential fit to 670 energies, a few hours on a single core is usually sufficient to produce a potential with R=12%–13% (see Equation. 9 in main-text for definition). To ensure a maximally optimized potential however (R=12%), a run-time of 24 hours is recommended. To optimize a RF-MEAM potential, a further 24 hours should be allowed. One will already find an improvement over the EAM using just a single core, however to ensure a maximally optimized potential, one should run several instances of MEAMfit in parallel.

Dislocation modeling in bcc lithium: A comparison between continuum and atomistic predictions in the modified embedded atoms method

In this study, the modified embedded-atom method (MEAM) was applied to compare the predictions of dislocation core properties obtained by molecular statics with the continuum predictions obtained in the framework of the simplified 1D-Peierls–Nabarro model. To this end, a set of four fictive Li potentials in the MEAM framework was proposed with the condition that all four potentials reproduce the same elastic constants, the same transition energies between bcc and fcc crystal structures, and between bcc and hcp crystal structures, while the unstable stacking fault energy on the plane {110} in the direction <111> was varied around the value predicted by first-principles. Within these potentials, direct atomistic calculations were performed to evaluate dislocation core properties such as dislocation half width and Peierls stress and the results were compared with continuum predictions. We found that the trends predicted by the Peierls–Nabarro model, i.e. (i) a decrease of the dislocation half width with increasing unstable stacking fault energy, and (ii) an increase of the Peierls stress with increasing the magnitude of the unstable stacking fault energy, were recovered using atomic calculations in the MEAM framework. Moreover, the magnitude of the dislocation half width and the Peierls stress calculated in the MEAM framework are in good agreement with the Peierls–Nabarro predictions when the dislocation half width is determined using a generic strategy. Specifically, the dislocation half width is defined as the distance for which the disregistery is included between b/4 and 3b/4. It was, therefore, demonstrated herein that the set of fictive potentials could be parameterized in the MEAM framework to validate or to disprove the continuum theory using atomistic methods.

Nitrogen vacancy, self-interstitial diffusion, and Frenkel-pair formation/dissociation inB1TiN studied byab initioand classical molecular dynamics with optimized potentials

We use ab initio and classical molecular dynamics (AIMD and CMD) based on the modified embedded-atom method (MEAM) potential to simulate diffusion of N vacancy and N self-interstitial point defects in $B1$ TiN. TiN MEAM parameters are optimized to obtain CMD nitrogen point-defect jump rates in agreement with AIMD predictions, as well as an excellent description of $\mathrm{Ti}{\mathrm{N}}_{x}(\ensuremath{\sim}0.7&lt;x\ensuremath{\le}1)$ elastic, thermal, and structural properties. We determine N dilute-point-defect diffusion pathways, activation energies, attempt frequencies, and diffusion coefficients as a function of temperature. In addition, the MD simulations presented in this paper reveal an unanticipated atomistic process, which controls the spontaneous formation of N self-interstitial/N vacancy $({\mathrm{N}}^{\mathrm{I}}/{\mathrm{N}}^{\mathrm{V}})$ pairs (Frenkel pairs), in defect-free TiN. This entails that the N lattice atom leaves its bulk position and bonds to a neighboring N lattice atom. In most cases, Frenkel-pair ${\mathrm{N}}^{\mathrm{I}}$ and ${\mathrm{N}}^{\mathrm{V}}$ recombine within a fraction of ns; \ensuremath{\sim}50% of these processes result in the exchange of two nitrogen lattice atoms $(\mathrm{N}\ensuremath{-}{\mathrm{N}}^{\mathrm{Exc}})$. Occasionally, however, Frenkel-pair N-interstitial atoms permanently escape from the anion vacancy site, thus producing unpaired ${\mathrm{N}}^{\mathrm{I}}$ and ${\mathrm{N}}^{\mathrm{V}}$ point defects.

First-principle and molecular dynamics calculations for physical properties of Ni–Sn alloy system

The structural, elastic, vibrational and thermodynamic properties of binary Ni–Sn compounds are investigated by first-principle (FP) calculations. A set of modified embedded atom method (MEAM) potential for Ni–Sn system is proposed on the basis of the FP energy–volume relationships for the three compounds hP8-Ni3Sn, oP20-Ni3Sn2 and mC14-Ni3Sn4. The polycrystalline elastic properties of Ni–Sn compounds generally decrease with the increase of Sn atom fractions, and all of the isotropic intermetallics exhibit some extent of intrinsic ductility. Among all the structures, oP20-Ni3Sn2 has the highest degree of isotropy, whereas the others show different degrees of anisotropy. The high temperature phase cF16-Ni3Sn is both mechanically and dynamically unstable at ambient condition. By considering the lattice vibrations under quasiharmonic phonon or Debye approximation, the thermodynamic properties of Ni–Sn compounds such as the enthalpies and specific heats can be well predicted from FP or MEAM calculations as well as the finite temperature molecular dynamics simulations. Furthermore, the high temperature properties such as the surface tensions of Ni–Sn alloys can also be calculated from the MEAM potential.

Quantitative modeling of the equilibration of two-phase solid-liquid Fe by atomistic simulations on diffusive time scales

(Received 10 July 2014; revised manuscript received 10 December 2014; published 12 January 2015) In this paper, molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM) and a phase-field crystal (PFC) model are utilized to quantitatively investigate the solid-liquid properties of Fe. A set of second nearest-neighbor MEAM parameters for high-temperature applications are developed for Fe, and the solid-liquid coexisting approach is utilized in MD simulations to accurately calculate the melting point, expansion in melting, latent heat, and solid-liquid interface free energy, and surface anisotropy. The required input properties to determine the PFC model parameters, such as liquid structure factor and fluctuations of atoms in the solid, are also calculated from MD simulations. The PFC parameters are calculated utilizing an iterative procedure from the inputs of MD simulations. The solid-liquid interface free energy and surface anisotropy are calculated using the PFC simulations. Very good agreement is observed between the results of our calculations from MEAM-MD and PFC simulations and the available modeling and experimental results in the literature. As an application of the developed model, the grain boundary free energy of Fe is calculated using the PFC model and the results are compared against experiments.

Two-phase solid–liquid coexistence of Ni, Cu, and Al by molecular dynamics simulations using the modified embedded-atom method

The two-phase solid–liquid coexisting structures of Ni, Cu, and Al are studied by molecular dynamics (MD) simulations using the second nearest-neighbor (2NN) modified-embedded atom method (MEAM) potential. For this purpose, the existing 2NN-MEAM parameters for Ni and Cu were modified to make them suitable for the MD simulations of the problems related to the two-phase solid–liquid coexistence of these elements. Using these potentials, we compare calculated low-temperature properties of Ni, Cu, and Al, such as elastic constants, structural energy differences, vacancy formation energy, stacking fault energies, surface energies, specific heat and thermal expansion coefficient with experimental data. The solid–liquid coexistence approach is utilized to accurately calculate the melting points of Ni, Cu, and Al. The MD calculations of the expansion in melting, latent heat and the liquid structure factor are also compared with experimental data. In addition, the solid–liquid interface free energy and surface anisotropy of the elements are determined from the interface fluctuations, and the predictions are compared to the experimental and computational data in the literature.

Hierarchical Bridging Between Ab Initio and Atomistic Level Computations: Calibrating the Modified Embedded Atom Method (MEAM) Potential (Part A)

This article provides a sequential calibration methodology for correlating the Modified Embedded Atom Method (MEAM) potential parameters to lower length scale calculation results or experimental data. We developed a graphical interactive MATLAB program called the MEAM Potential Calibration (MPC) tool that provides an interface with the large-scale atomistic/molecular massively parallel simulator. The MPC tool supports a rigorous yet fairly simple calibration methodology for determining the MEAM potential parameters. A pure aluminum system is used as an example to demonstrate the bridging methodology; however, the tool can be used for any material.

Integrated Computational Materials Engineering: A Multi-Scale Approach

Computational materials science and engineering has a strong potential for developing robust simulation-based designs for optimizing materials, components, and engineering structures. Integrated computational materials engineering (ICME) provides practical solutions for engineering design tasks and has been recognized by the National Academy of Engineering (NAE Report 2008). The vital role of materials in design as well as the importance of computation in materials engineering necessitate understanding structure, properties, processing, and performance of materials and designed components. Thus, multiscale modeling has extended into solid mechanics, fluid mechanics, materials science, physics, mathematics, biology, and chemistry. ICME couples quantum scales with macroscales. It also allows the integration of materials processing and product performance for simulation-based manufacturing. These advances are analogous to transistor models that have led to complex logic operations and concurrent multilevel simulations. ICME can reduce product development time and costs by minimizing design cycles and facilitating cost-effective design optimization. These benefits have the potential to drive the utilization of multiscale modeling in various industrial sectors. The ‘‘integrated’’ part of ICME strongly emphasizes synergistic systems and interdisciplinary thinking accompanied by multiscale modeling methods. However, a key challenge is to link the various disciplines. Mathematics and statistics play a critical role and form a strong basis for modeling strategies. The terms ‘‘bottom-up’’ and ‘‘top-down’’ are of particular interest. The following characteristics are critical for these approaches: (I) length scales, (II) degrees of freedom and boundary conditions, (III) geometric and energy constraints, (IV) suitable numerical model implementation, (V) determining right sequence of calculations to be performed, (VI) determining variables and equations describing structure–property function, (VII) analyzing the cause–effect relationships using numerical methods, (VIII) verifying effects by experimental approaches before using the developed theory for next higher scales, and (IX) estimating the uncertainty in simulations and experiments to help develop a concrete multiscale modeling approach. This issue of JOM presents nine invited research and review articles. These articles discuss the importance of the ICME approach in refining conventional material and component processing methods as well as advanced materials processing. The article by Ghosh et al. discusses multiscale modeling of heterogeneous metals and alloys. They comprehensively address the problems related to hierarchical-concurrent multilevel or multiscale modeling methods for ductile fracture and nested dual-stage homogenization method for microstructure-based models for cast Al alloys. The two articles by Horstemeyer and colleagues detail the development and deployment of the modified embedded atom method (MEAM). The authors focus on the MATLAB-based MEAM potential calibration tool and interface with LAMMPS. The technique is used for studying aluminum system. To further define the ICME in ‘‘completeness,’’ the article by Liu et al. discusses case studies focused on three examples, where experiments are integrated with computation aspects. The modeling methods described include artificial neural networks, dislocation dynamics, and CALPHAD approach. Asadi et al. discuss the phase-field crystal model and multiscale analysis of solid–liquid structures. The article also compares various phase-field models for calculating solid–liquid interfaces. Bryan et al. demonstrate alloy design using the ICME-based Nitin Chopra is the Guest Editor for the ICME Committee of the TMS Materials Processing & Manufacturing Division, and coordinator of the topic Multi-Scale Modeling: Concurrent and Hierarchical Methods in this issue. JOM, Vol. 67, No. 1, 2015