# Formation of hexagonal close packing at a grain boundary in gold by the dissociation of a dense array of crystal lattice dislocations

- 188 Downloads
- 1 Citations

## Abstract

We analyze a thin (~1 nm) hexagonal-close-packed (HCP) intergranular layer at a 29° 〈110〉 tilt grain boundary in gold. Our analysis, which is based on HRTEM observations and atomistic calculations, shows that this boundary consists of a dense array of 60° 1/2〈110〉 crystal lattice dislocations that are distributed one to every two {111} planes. These dislocations dissociate into paired Shockley partial dislocations, creating a stacking fault on every other plane and thereby producing the …*abab*…, or HCP, stacking sequence. This distribution of dislocations is consistent both with the measured intergranular misorientation and with the calculated rigid-body translation along the tilt axis. By establishing the interfacial dislocation arrangement, we also show how the HCP layer at the 29° boundary observed here is geometrically related to that found previously at the 80.6° Σ = 43 〈110〉 boundary. This result helps to link dislocation-based descriptions for boundary structures between the high- and low-angle misorientation regimes.

## Keywords

Partial Dislocation Dense Array Tilt Boundary Embed Atom Method Tilt Axis## Notes

### Acknowledgements

Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy, National Nuclear Security Administration, under Contract DE-AC04-94AL85000. This work was supported in part by the DOE Office of Basic Energy Science, Division of Materials Sciences. The authors acknowledge helpful comments from J. Sugar, S. Foiles, and the anonymous reviewer.

## References

- 1.Krakow W, Smith DA (1987) Ultramicroscopy 22:47CrossRefGoogle Scholar
- 2.Merkle KL (1990) Colloq Phys C1 51:251Google Scholar
- 3.Ernst F, Finnis MW, Hofmann D, Muschik T, Schönberger U, Wolf U, Methfessel M (1992) Phys Rev Lett 66:991Google Scholar
- 4.Wolf U, Ernst F, Muschik T, Finnis MW, Fischmeister HF (1992) Philos Mag A 66:991CrossRefGoogle Scholar
- 5.Merkle KL (1994) J Phys Chem Solids 55:991CrossRefGoogle Scholar
- 6.Medlin DL, Campbell GH, Carter CB (1998) Acta Mater 46:5135CrossRefGoogle Scholar
- 7.Radetic T, Lançon F, Dahmen U (2002) Phys Rev Lett 89:85502CrossRefGoogle Scholar
- 8.Brown JA, Mishin Y (2007) Phys Rev B 76:134118CrossRefGoogle Scholar
- 9.Tschopp MA, Tucker GJ, McDowell DL (2007) Acta Mater 55:3959CrossRefGoogle Scholar
- 10.Rittner JD, Seidman DN (1996) Phys Rev B 54:6999CrossRefGoogle Scholar
- 11.Medlin DL, Foiles SM, Cohen D (2001) Acta Mater 49:3689CrossRefGoogle Scholar
- 12.Lucadamo G, Medlin DL (2003) Science 300:1272CrossRefGoogle Scholar
- 13.Jenkins ML (1972) Philos Mag 36:747CrossRefGoogle Scholar
- 14.Balk TJ, Hemker KJ (2001) Philos Mag A 81:1507CrossRefGoogle Scholar
- 15.Thompson N (1953) Proc Phys Soc Sect B 66B:481CrossRefGoogle Scholar
- 16.Hirth JP, Lothe J (1992) Theory of dislocations. Krieger Publishing Company, Malabar, FLGoogle Scholar
- 17.Read WT (1953) Dislocations in crystals. McGraw-Hill, New York, p 17Google Scholar
- 18.Sutton AP, Balluffi RW (1995) Interfaces in crystalline materials. Clarendon Press, Oxford, p 70Google Scholar
- 19.Daw MS, Baskes MI (1983) Phys Rev Lett 50:1285CrossRefGoogle Scholar
- 20.Daw MS, Baskes MI (1984) Phys Rev B 29:6443CrossRefGoogle Scholar
- 21.Dash S, Brown N (1963) Acta Metall 35:1067CrossRefGoogle Scholar
- 22.Medlin DL, Cohen D, Pond RC (2003) Philos Mag Lett 83(4):223CrossRefGoogle Scholar
- 23.Pond RC, Medlin DL, Serra A (2006) Philos Mag 86(29–30):4667CrossRefGoogle Scholar
- 24.Hirth JP (1994) J Phys Chem Solids 55:985CrossRefGoogle Scholar
- 25.Pond RC, Celotto S, Hirth JP (2003) Acta Mater 51:5385CrossRefGoogle Scholar