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Yield Stress of Nano- and Micro- Multilayers

  • P. M. Hazzledine (a1) and S. I. Rao (a1)

Abstract

An outline theory is given for the strengthening in polycrystalline and ‘single crystal’ multilayers. The model is based on the Hall-Petch theory applied to both the soft mode (in plane) and hard mode (cross plane) of deformation. In this theory the parameters to be evaluated are a Taylor factor M, the shear stress τ0 to move a dislocation within a multilayer and τ*, the shear stress needed to push a dislocation over a grain or interphase boundary. All three parameters are material- specific and attention is focussed on coherent multilayers of γ TiAl with micron thick layers and Cu-Ni with nanometer thick layers. M and some components of τ* are estimated classically. The remaining components of τ* and some components of τ0 are estimated from embedded atom simulations. The model captures the main experimental facts, that γTiAl is plastically very anisotropic with a rising yield stress as the lamellar thickness is refined and that Cu-Ni displays a peak in the yield stress at a layer thickness of approximately 10nm.

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1. Eshelby, J. D., Phys. Stat. Sol. 3, 2057 (1963).
2. Li, J. C. M. and Liu, G. C. T., Phil. Mag. 15, 1059 (1967).
3. Li, J. C. M. and Chou, Y. T., Met. Trans. 1, 1145 (1970).
4. Yamaguchi, M. and Umakoshi, Y., Prog. Mater. Sci. 34, 1 (1990).
5. Yamaguchi, M., Inui, H., Kishida, K., Matsumuro, M. and Shirai, Y., MRS Proc. 364, 3 (1995).
6. Rao, S. I., Woodward, C., Simmons, J. and Dimiduk, D. M., MRS Proc. 364, 129 (1995).
7. Inui, H., Oh, M. H., Nakamura, A. and Yamaguchi, M., Acta Metall. Mater. 40, 3095 (1992).
8. Fu, C. L. and Yoo, M. H., MRS Proc. 186, 265 (1990).
9. Nakano, T., Yokoyama, A. and Umakoshi, Y., Scripta Metall. Mater., 27, 1253 (1992).
10. Hazzledine, P. M., Kad, B. K. and Mendiratta, M. G., MRS Proc. 308, 725 (1993).
11. Rao, S. I., Woodward, C. and Hazzledine, P. M., MRS Proc. 319, 285 (1994).
12. Koehler, J. S., Phys. Rev. B2, 547 (1970).
13. Rao, S. I., Hazzledine, P. M. and Dimiduk, D. M., MRS Proc. 362, 67 (1995).
14. Frank, F. C. and Merwe, J. H. van der, Proc. Roy. Soc. London A198, 216 (1953).

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