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Sub-atomic Dynamic simulations have been carried out on some single-crystal
hexagonal metals, HCP nanowires (Cd, Co, Mg, Ti, and Zr) upon application of uniaxial
tension with a speed of 20 m/s and to investigate the nature of deformation and fracture. The
deformation corresponds to the direction <0001> plane. A many-body interatomic potential
for HCP nanowires within the second-moment approximation of the tight-binding model (the
Cleri-Rosato potentials) was employed to carry out three dimensional MD simulations.
A computer experiment is performed at a temperature 300K. The stored energy diagrams
obtained at various time by the MD simulations of the tensile specimens of these metallic
nanowires show a rapid increase in stress up to a maximum followed by a gradual drop to
zero when the specimen fails by ductile fracture. The feature of deformation energy can be
divided into three regions: quasi-elastic, plastic and failure. The nature of deformation,
slipping, twinning and necking were studied. Stress decreased with increasing volume and the
breaking position increases. The results showed that breaking position depended on the
nanowire length. From this, it appears that Cleri-Rosato potentials make good represent for
the deformation behavior of HCP metallic nanowires.
Keywords: molecular dynamics, uniaxial tension, Cleri-Rosato, nanowires, tight-binding and failure |
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