ISSN:
1573-4900
Keywords:
Atomistic simulation
;
Bond order potential
;
Iron
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A new semi-empirical potential for Fe based on the quantum chemistry concept of bond order has been developed. The potential consists of two parts: the repulsive short-range exponential potential, and the attractive potential, also of the exponential form, with a bond-order prefactor. The latter depends on angles between the Fe-Fe bonds, and uses the environmental parameter similar to that of the Tersoff bond-order potential for tetrahedrally bonded semiconductors. The bond order function (depending on the above environmental parameter), however, is of a more general form than that of the Tersoff potential. The new potential was calibrated using the traditional fitting to the Universal Scaling and the equilibrium volume and cohesive energy of BCC Fe. The introduced 'punishment functions' also directed the multi-variate minimization process towards minimizing the deviations between the calculated and experimental values of the elastic moduli C′ and C44, the energies of FCC and HCP Fe modifications, and the (111) free surface energy. With the total of 15 fitted parameters, the potential reproduces with only minor deviations the elastic moduli, the volume–pressure equation of states in BCC phase, the energies in FCC and HCP modifications, the BCC-HCP phase transformation under pressure, and the energy of the (111) free surface. Other tests of the new potential are being currently performed. The potential will be used in atomistic simulations of lattice stability, and deformation and chemisorption processes in Fe.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008730606251
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