Stress-enhanced grain growth in a nanocrystalline material by molecular-dynamics simulation.
Molecular-dynamics simulations are used to elucidate the coupling between grain growth and grain-boundary diffusion creep in a polycrystal consisting of 25 grains with an average grain size of about 15 nm and a columnar grain shape. Consistent with our earlier simulations of grain-boundary diffusion creep, albeit in the absence of grain growth, we find that initially, i.e. prior to the onset of significant grain growth, the deformation proceeds via the mechanism of Coble creep. Also, consistent with our earlier grain-growth simulations in the absence of stress, two growth mechanisms are observed during the deformation: growth due to curvature-driven GB migration and growth resulting from grain rotation-induced grain coalescence. The comparison of the grain growth observed in the presence of the applied stress with that solely in response to temperature as the driving force enables us to identify the mechanisms by which external stress affects grain growth. In particular, we find that both GB migration and grain rotation are accelerated by the deformation.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 961228
- Report Number(s):
- ANL/MSD/JA-45564
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 ; Apr. 18, 2003 Vol. 51; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
Grain-boundary diffusion creep in nanocrystalline palladium by molecular-dynamics simulation.
MOLECULAR DYNAMICS STUDY OF DIFFUSIONAL CREEP IN NANOCRYSTALLINE UO2