Large deformation and amorphization of Ni nanowires under uniaxial strain:A molecular dynamics study

Citation
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
Citations number
18
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
62
Issue
24
Year of publication
2000
Pages
16950 - 16955
Database
ISI
SICI code
0163-1829(200012)62:24<16950:LDAAON>2.0.ZU;2-G
Abstract
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.