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A many-body interatomic potential was used for Nickel (Ni) crystal with facecentered cubic (FCC) lattice and Titanium (Ti) with hexagonal close-packed (HCP) lattice
and Nitinol alloys within the second-moment approximation. The tight-binding model (the
Cleri and Rosato potentials) was employed to carry out three dimensional molecular dynamics
simulations upon application of uniaxial tension at nanoscale of studied materials, which
contained various vacancy rates. We performed molecular dynamics (MD) simulations to
study the yield mechanisms in Ni and Ti nanowires and Nitinol alloys. The coupled effects of
various shapes, sizes, and locations of vacancy defects on the mechanical strength and
structural deformation of nanowires are presented. The formation energies of vacancy defects
are also evaluated. It was found that as the number of vacancies increases, the yield stress
decreases. The results showed that breaking time changes with the increase in number of
vacancy. To understand the effects of the vacancies on the mechanical properties of Ni and Ti
nanowires and Nitinol alloys, tensile and fatigue tests are simulated.
Keywords: many-body, Nitinol, alloys, vacancy, defects |
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