Deformation mechanism crossover and mechanical behaviour in nanocrystalline materials.
We use molecular dynamics simulations to elucidate the transition with decreasing grain size from a dislocation- to a grain-boundary-based deformation mechanism in nanocrystalline fcc metals. Our simulations reveal that this crossover is accompanied by a pronounced transition in the mechanical behaviour of the material; namely, at the grain size where the crossover occurs (the 'strongest size'), the strain rate under tensile elongation goes through a minimum. This simultaneous transition in both the deformation mechanism and the corresponding mechanical behaviour offers an explanation for the experimentally observed crossover in the yield strength of nanocrystalline materials, from Hall-Petch hardening to 'inverse Hall-Petch' softening.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 961350
- Report Number(s):
- ANL/MSD/JA-46959
- Journal Information:
- Philos. Mag. Lett., Journal Name: Philos. Mag. Lett. Journal Issue: 6 ; Jun. 2003 Vol. 83; ISSN PMLEEG; ISSN 0950-0839
- Country of Publication:
- United States
- Language:
- ENGLISH
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