Papers by Keyword: Modified Embedded Atom Method

Abstract: Aluminum-Iron-Silicon (Al-Fe-Si) alloys are extremely applied in many specific industries, such as aerospace and automobiles. Their atomic concentration influences the mechanical behavior of the investigated τ_4-Al₃Fe₂Si and τ_12-Al₃FeSi₂ phases. The uniaxial-tensile deformation is used to compare their structural evolution under the same conditions.Atomic displacement and mechanical behavior have an interest in the elastic and plastic areas. Stress-Strain responses and Radial Distribution Function (RDF) are required. Further, atomic simulations using molecular dynamics demonstrate the change occurs. Its process is carried out at a strain rate of 21×10¹⁰ s^-1 using the NPT (isothermal-isobaric) with roughly 20 700 atoms at a pressure of 10⁵ Pa. Furthermore, using a Nosée Hoover thermostat at the temperature of 300 k is decisive.The Modified Embedded Atoms Method (MEAM) is the applied potential between Al, Fe, and Si atoms. The elastic modulus and single pair atomic correlation before and after straining are increased by this method. The atomic correlations are shown in short- and long-range order and the τ₁₂-Al₃Fe₂Si phase illustrates stronger properties compared to τ_4-Al₃Fe₂Si phase. Our results underscore an important variation associated with the change of iron and silicon concentration. More specifics are covered in the selection paper.

Abstract: In this work, structural stability and thermal transformation of Pt-Sn bimetallic nano clusters are studied by molecular dynamics simulations, combined with the modified embedded atom method. For a more accurate description of the interatomic interactions, new Modified Embedded Atom Method alloying parameters for Pt-Sn are derived based on ab initio density functional theory calculations. The calculated Gibbs free energies of formation show that all kinds of structures are energetically favorable and the most stable structure is solid solution cluster, and then the core/shell, and eutectic-like cluster. For whatever compositions the eutectic-like clusters must transform into one pure Sn cluster and one Pt core/Sn shell cluster up to certain temperature during heating process, the Sn coverage on Pt core is dependent on its composition. For solid solution and Pt core/Sn shell or Sn core/Pt shell, once the structure forms, it can keep basically unchanged from the point of view of elemental distribution. Surface segregation is not apparent observed.

Abstract: The crack propagation for pure Magnesium at an atomic scale level under external loading was carried out by using a molecular dynamics method. In this study, the Modified Embedded Atom Method (MEAM) was used to characterize the interactions of atoms and the Newtonian equations were solved by Velocity-Verlet algorithm. The crack propagation and failure processes were observed around the crack tip. The calculation results reveal that vacancies were formed near the crack tip during the failure processes for pure Magnesium, and the coalescence between crack tip and vacancies induced the crack growth with the increase in loading.

Abstract: The modified embedded atom method (MEAM) can describe the physical properties of bulk systems for a wide range of advanced engineering materials. However, the MEAM is found to return negative surface energy for Li(100), Li(110) and Li(111), if the relaxation of atomic positions on the surface is taken into account. In order to solve this problem, a new scheme of MEAM for lithium has been developed, by modifying the expression of embedding function. In this work, the new scheme is also applied to the other alkali metals, and the parameter sets of MEAM have been determined by fitting to not only bulk properties but also some non-bulk properties. The new MEAM potentials for alkali metals have been applied to calculate the elastic stiffness of crystal, the vacancy formation energy, the surface energies for low index crystal faces and the bond length and the binding energy for dimer. The results have been compared with experimental values.