Ps. Branicio et Jp. Rino, Large deformation and amorphization of Ni nanowires under uniaxial strain:A molecular dynamics study, PHYS REV B, 62(24), 2000, pp. 16950-16955
Molecular-dynamics simulations were employed to study deformations on nicke
l nanowires subjected to uniaxial strain at 300 K using a recently reported
embedded-atom (many body) model potential. This embedded-atom model can re
produce exactly the experimental second-order and third-order elastic modul
i as well as the phase stability, equation of state and phonon frequency sp
ectra are also in good agreement with experiments. Strong influence was obs
erved in the Young modulus and force constant due to surface effects when c
onsidering nanowires with different cross sections. Applying strain rates,
from 0.05 to 15% ps(-1), we found elastic behavior up to 11.5% strain with
corresponding stress of 9.4 GPa. At low strain rates (<0.05% ps(-1)) the sy
stem passes through plastic deformations although keeping the crystalline s
tructure. This ductile process is showed by several snapshots. At this low
strain rate regime we observed that the nanowires shows superplasticity. Fo
r high strain rates (<greater than or equal to>7% ps(-1)) the system change
s continuously from crystalline to amorphous phase. Although this amorphiza
tion occurs with no use of liquid quenching or introduction of chemical or
physical disorder, so being a different and interesting process, the amorph
ous resulted is unstable. We studied this instability monitoring the recrys
tallization process.