MEAM interatomic potentials of Ni, Re, and Ni-Re alloys for atomistic fracture simulations

Second nearest neighbor modified embedded atom method (2NN-MEAM) interatomic potentials are developed for the Ni, Re, and Ni-Re binaries. To construct the potentials, density functional theory (DFT) calculations have been employed to calculate fundamental physical properties that play a dominant role in fracture. The potentials are validated to accurately reproduce material properties that correlate with material’s fracture behavior. The thus constructed potentials were applied to perform large scale simulations of mode I fracture in Ni and Ni-Re binaries with low Re content. Substitutional Re did not alter the ductile nature of crack propagation, though it resulted in a monotonous increase of the critical stress intensity factor with Re content.

Stability of supratransmission waves in a crystal of A3B stoichiometry upon interaction with single dislocations

Supratransmission waves are stable objects that can exist in different discrete environments. In this paper, we consider the interaction of such waves with single edge dislocations of various configurations in a crystal with A3B stoichiometry. The model was a Pt3Al crystal, the potential obtained by the embedded atom method was used to describe the interaction of its atoms. Quantitative characteristics of the wave were obtained before and after the interaction. It is found that the degree of energy dissipation by dislocations depends on the mutual orientation of the wave front and the extra plane of the dislocation. Numerical estimates are made for four different configurations. The results obtained can be useful in studying the propagation of soliton-type waves in defect crystals of various compositions.

Modified Embedded-Atom Interatomic Potential Parameters of the Ti–Cr Binary and Ti–Cr–N Ternary Systems

The second nearest-neighbor modified embedded-atom method (2NN MEAM) potential parameters of the Ti–Cr binary and Ti–Cr–N ternary systems are optimized in accordance with the 2NN MEAM method. The novel constructed potential parameters can well reproduce the multiple fundamental physical characteristics of binary and ternary systems and reasonably agree with the first-principles calculation or experimental data. Thus, the newly constructed 2NN MEAM potential parameters can be used for atomic simulations to determine the underlying principle of the hardness enhancement of TiN/CrN multilayered coatings.

Atomistic simulations of Ag–Cu–Sn alloys based on a new modified embedded-atom method interatomic potential

An interatomic potential for the ternary Ag–Cu–Sn system, an important material system related to the applications of lead-free solders, is developed on the basis of the second nearest-neighbor modified embedded-atom-method formalism. Potential parameters for the ternary and related binary systems are determined based on the recently improved unary description of pure Sn and the present improvements to the unary descriptions of pure Ag and Cu. To ensure the sufficient performance of atomistic simulations in various applications, the optimization of potential parameters is conducted based on the force-matching method that utilizes density functional theory predictions of energies and forces on various atomic configurations. We validate that the developed interatomic potential exhibits sufficient accuracy and transferability to various physical properties of pure metals, intermetallic compounds, solid solutions, and liquid solutions. The proposed interatomic potential can be straightforwardly used in future studies to investigate atomic-scale phenomena in soldering applications. Graphical abstract

Fabrication of Magnesium-Aluminum Composites under High-Pressure Torsion: Atomistic Simulation

The aluminum–magnesium (Al–Mg) composite materials possess a large potential value in practical application due to their excellent properties. Molecular dynamics with the embedded atom method potentials is applied to study Al–Mg interface bonding during deformation-temperature treatment. The study of fabrication techniques to obtain composites with improved mechanical properties, and dynamics and kinetics of atom mixture are of high importance. The loading scheme used in the present work is the simplification of the scenario, experimentally observed previously to obtain Al–Cu and Al–Nb composites. It is shown that shear strain has a crucial role in the mixture process. The results indicated that the symmetrical atomic movement occurred in the Mg–Al interface during deformation. Tensile tests showed that fracture occurred in the Mg part of the final composite sample, which means that the interlayer region where the mixing of Mg, and Al atoms observed is much stronger than the pure Mg part.

Determinação das características estruturais e mecânicas da liga de alta entropia Hf-Nb-Ta-Zr

Neste artigo, os comportamentos estrutural e mecânico da liga equiatômica de alta entropia Hf-Nb-Ta-Zr foram estudados mediante simulações computacionais de dinâmica molecular. As simulações foram realizadas no código livre LAMMPS, em um sistema composto de 154.000 átomos que interagiram sob o potencial Embedded Atom Method (EAM). O estudo focou na estrutura cúbica de corpo centrado (CCC). Esta estrutura apresenta a maior estabilidade estrutural ou a menor energia potencial a 0 K. A liga foi submetida a ensaios de nanoindentação utilizando um penetrador virtual esférico de diâmetro de 40 Å. Ensaiou-se à temperatura de 10 K para eliminar as contribuições térmicas dos átomos, em três planos cristalográficos (001), (011) e (111), e identificar efeitos de anisotropia. A evolução estrutural da liga foi analisada mediante as funções de distribuição radial parcial (PRDF), funções de distribuição radial total (TRDF) e também por difração de raios-X. As curvas de carregamento-descarregamento mostraram que a nanoindentação na superfície correspondente ao plano (011) requer a maior força de indentação, de cerca de 142 nN, enquanto que o plano (111) conduz à maior deformação elástica antes do início da deformação plástica.