کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1449897 | 988717 | 2007 | 11 صفحه PDF | دانلود رایگان |
Molecular dynamics simulation is employed to investigate the plastic flows in nanocrystalline (nc) hexagonal close-packed cobalt under uniaxial tensile deformation. In nc-Co samples modeled by a semi-empirical tight-binding potential, different deformation behaviors such as nucleation and growth of disordered atom segments (DAS) inside grains, deformation-induced hexagonal close-packed to faced-centered cubic transformation, partial dislocation activities are identified at different grain sizes (4–12 nm). At high stresses (1.2–3.2 GPa) and low temperatures (77–470 K), growth of DAS and their interaction with stacking faults are found to dominate the deformation process, even when the grain size is as small as 4 nm. A model for plastic flow generated by DAS inside grains is proposed. The strain rates and the inverse Hall–Petch-like behaviors in nc-Co with sub-10 nm grain sizes can be well described by the DAS plastic-flow model.
Journal: Acta Materialia - Volume 55, Issue 1, January 2007, Pages 149–159