Grain boundaries of polycrystalline copper deformed under creep conditions have been studied in a 1000 kV electron microscope. Twin boundaries show dense dislocation arrangements, while high-angle boundaries are almost dislocation-free. Cavities are observed in the very early stages of formation. They are always found associated with obstacles in the grain boundaries such as triple points and kinks. These results are discussed in terms of a previously proposed model for grain-boundary sliding. The implications for the deformation of a polycrystalline material at various temperatures are also considered.
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References
1.
JohannessonT. and ThölenA., Phil. Mag., 1970, 21, 1223.
2.
TunstallW. J., ‘Proceedings of the 7th International Conference on Electron Microscopy’ (Grenoble1970), Vol. II, p.313. 1970: Paris(Societe Française de Microscopie Electronique).
3.
LinT. L. and McLeanD., Metal Sci. J., 1968, 2, 108.
4.
GleiterH., HornbogenE., and Bar°G., Acta Met., 1968, 16, 1053.
5.
IshidaY. and McLeanD., Metal Sci. J., 1967, 1, 171.
6.
ShewmonP. G., ‘Diffusion in Solids’.1963: New York and London(McGraw-Hill).
7.
GrabskiM. W. and KorskiR., Phil. Mag., 1970, 22, 707.
8.
TurnerP. A., PhD Thesis, Univ. London,1965.
9.
GarofaloF., ‘Fundamentals of Creep and Creep-Rupture in Metals’.1965: New York, &c. (Macmillan).
10.
AshbyM. F., RajR., and GifkinsR. C., Scripta Met., 1970, 4, 737.
11.
ChouY. T., GarofaloF., and WhitmoreR. W., Acta Met., 1960, 8, 480.
