Papers by Keyword: Interatomic Potentials

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Authors: Jing Sun, Shuo Huang, Jiang Shen, Ping Qian
Abstract: The effect of cobalt on the structural properties of intermetallic Tb3(Fe28-xCox)V1.0 with Nd3(Fe,Ti)29 structure has been studied by using interatomic pair potentials obtained through the lattice inversion method. Calculated results show that the order of site preference of cobalt is 8j(Fe8), 4e(Fe11) and 2c(Fe1) which is in good agreement with experimental results. And the calculated lattice constants coincide quite well with experimental values. All these prove the effectiveness of interatomic pair potentials obtained through the lattice inversion method in the description of rare-earth materials.
Authors: Zhen Feng Zhang, Ping Qian, Jin Chun Li, Jiang Shen
Abstract: The phase stability and site preference of transition metal carbides Cr in Fe7-xCrxC3 are studied based on the pair potentials obtained by the lattice inversion method. The lattice constants and cohesive energy of Fe7-xCrxC3 with the content x are calculated. The results show that Cr atoms substitute for Fe with a strong preference for the 6c1 sites and the order of site preference is 6c1, 6c2 and 2b. Calculated lattice parameters are in good agreement with the experimental data. Moreover, the total and partial phonon densities of states are first evaluated for the Fe7-xCrxC3 compounds with the hexagonal structure. We also provide some information on the vibrational properties of transition metal carbides, such as the specific heat and Debye temperature were also evaluated.
Authors: Ling Ping Xiao
Abstract: The structural properties of GdFe2-xTx (T=Ti, Al) and their hydrides are studied by using inter-atomic potentials based on Chens lattice inversion technique. The results show that GdFe2-xAlx crystallizes with the MgZn2 type phase in the range 0.35x0.7. And GdFe2-xTix crystallizes with the MgZn2 type phase has the lowest energy for 0x<0.17 and="" the="" tolerance="" is="" acceptable="" gdfe="" sub="">2-xTix compounds are stabilized in MgZn2 type phase with different Ti atoms content in the range 0.17<x0.6. Moreover, the calculated lattice constants coincide quite well with experimental values. All the results indicate the potentials are valid for studying the structural properties of the intermetallics.
Authors: Xiao Xu Wang, Ping Qian, Zhi Wei An, Zhen Feng Zhang, Jiang Shen, Nan Xian Chen
Abstract: An atomistic simulation of the structural properties of the Rh7-xTxB3 series, where T is Fe, Cr, Mn, has been carried out using interatomic pair potentials based on the lattice inversion method. Calculated results show T atoms can stabilize Rh7-xTxB3 with Th7Fe3-type structure, and T atoms substitute for Rh with a strong preference for the 2b sites. The phase stability of the intermetallics Rh7-xTxB3 is tested by many means including random atom shift, global deformation and high temperature disturbance under the control of the pair potentials. Calculated unit-cell parameters for Rh7-xTxB3 agree with the experimental data very well. All the above results indicate that the potentials are valid for studying the structural properties of these kinds of complex structure of transition metal boride.
Authors: Akinjide O. Oluwajobi, Xun Chen
Abstract: There is a need to choose appropriate interatomic empirical potentials for the molecular dynamics (MD) simulation of nanomachining, so as to represent chip formation and other cutting processes reliably. Popularly applied potentials namely; Lennard-Jones (LJ), Morse, Embedded Atom Method (EAM) and Tersoff were employed in the molecular dynamics simulation of nanometric machining of copper workpiece with diamond tool. The EAM potentials were used for the modelling of the copper-copper atom interactions. The pairs of EAM-Morse and EAM-LJ were used for the workpiece-tool (copper-diamond) atomic interface. The Tersoff potential was used for the carbon-carbon interactions in the diamond tool. Multi-pass simulations were carried out and it was observed that the EAM-LJ and the EAM-Morse pair potentials with the tool modelled as deformable with Tersoff potential were best suitable for the simulation. The former exhibit the lowest cutting forces and the latter has the lowest potential energy.
Authors: Wei Ping Dong, Zheng Chen
Abstract: Based on the phase field theory, the long-range order (LRO) parameter related interatomic potentials equations were utilized to calculate the interatomic potentials of L10-Ni3(Al,V), L12-Ni3Al and L12-Ni3(Al,V) phases varying with temperature and concentrations. Using these potentials, the simulated microstructure evolution and the order parameter with the time of Ni75Al20V5 ternary alloy are simulated at temperature 1000K during the early stage of the precipitation process in this research. Results testify that the precipitation sequence during the early stage of Ni75Al20V5 alloy is the disordered phase →L10 pre-precipitation phase →L12 equilibrium phase. Firstly, the nonstoichiometric L10 pre-precipitation phase formed by congruent ordering precipitation mechanism; secondly, the nonstoichiometric L12 phase formed by transforming from L10 phase; thirdly, the stoichiometric equilibrium L12 phase formed by spinodal decomposition precipitation mechanism. It is discovered that the precipitation mechanism (congruent ordering+ spinodal decomposition) process was closely related to free energy and interatomic potentials: L10 pre-precipitation phase’s free energies are higher and interatomic potentials are smaller than those of L12 equilibrium phase.
Authors: Takehiko Makino, Atsushi Kubo, Hiroki Iida, Shun Ichiro Tanaka
Abstract: Considering the uniqueness of wetting systems consisting of three components, namely, the surface, liquid and liquid/solid interface, it is desirable to construct interatomic potentials following a consistent policy. To investigate the physical meaning of the behavior in terms of the interatomic potentials, the wetting systems are modeled by simple two-body interatomic potentials derived using ab initio molecular orbital calculations for hypothetical clusters representing the above three components. For In and Sn liquid atoms, spreading occurs on a Cu (111) surface, while in contrast, liquid atoms penetrate the substrate and form a surface alloy in the case of a Pd (111) surface.
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