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Meso-to-Nano-scopic Polycrystal/Composite Strengthening

Published online by Cambridge University Press:  01 February 2011

R. W. Armstrong ,
H. Conrad  and
F. R. N. Nabarro
R. W. Armstrong
Affiliation:
AFRL/MNME, Eglin Air Force Base, FL 32542
H. Conrad
Affiliation:
Materials Science & Engineering, North Carolina State University, Raleigh, NC 27695
F. R. N. Nabarro
Affiliation:
School of Physics, University of the Witwatersrand, Johannesburg, SA
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Abstract

A great challenge associated with current investigations of the structural strength properties of nanometrically-scaled polycrystals and/or composite materials relates to quantitative description of the continuous transition in mechanical behaviors occurring when going over to such materials from those microstructural, and larger, scale material deformation properties seemingly well-understood and modeled during the research investigations of the previous century [1]. The consideration relates to whether the same dislocation generation/interaction mechanisms operating within the grain volumes of a conventional microstructured material, say, as compared in the same case for local deformations, dislocation or otherwise, at the grain boundary regions, are either additionally restricted from operation, or enhanced, for nanostructured materials. The deduced indication is that there should be a relatively smooth mechanical property transition, if any change at all, to be demonstrated here on the basis of available experimental and theoretical modeling results. The predicted smooth transition in behavior, however, may be upset, possibly, by failure to achieve the demanding quality control predictably needed for the combined considerations of: (1) structural characterization; (2) mechanical testing methods; and, (3) model computations, so as to allow quantification of the finer-scaled material behaviors. The combined property behavior is illustrated by application of effective low temperature grain boundary strengthening models at larger grain (or particle) sizes, then, transitioning to effective grain size weakening at the smallest grain sizes, with such weakening thought to occur because of otherwise normal high temperature diffusional or grain boundary weakening mechanisms being promoted somehow to become controlling in the practical “thought-to-be” low temperature regime.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 791: Symposium Q – Mechanical Properties of Nanostructured Materials and Nanocomposites , 2003 , Q3.6
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

1. Armstrong, R.W., in Encyclopedia of Materials: Science and Technology, edited by Buschow, K.H.J., Cahn, R.W., Flemings, M.C., Ilschner, B., Kramer, E.J. and Mahajan, S., (Elsevier Science Publishers, Oxford U.K., 2001), p. 7103.Google Scholar
2. Smith, T.R., Armstrong, R.W., Hazzledine, P.M., Masumura, R.A. and Pande, C.S., in Grain Size and Mechanical Properties – Fundamentals and Applications, edited by Otooni, M.A., Armstrong, R.W., Grant, N.J. and Ishizaki, K., (Mater. Res. Soc. Proc. 362, Pittsburgh, PA, 1995) p. 31.Google Scholar
3. Armstrong, R.W., Kramer, M.P., Wilson, W.H. and Zerilli, F.J., in Proc. Eighth Intern. Conf. on Composites Engineering (ICCE/8), edited by Hui, D., (Intern. Community for Composites Engineering and College of Engineering, Univ. New Orleans, LA, 2001) p. 41.Google Scholar
4. Armstrong, R.W., Lemkey, F.D. and Thompson, E.R., in Second Intern. Conf. on In-Situ Composites, (Xerox Publishers, N.Y., 1976), II, p. 476.Google Scholar
5. Lee, M.-Y. and Gurland, J., Mater. Sci. Eng. 33, 125 (1978).Google Scholar
6. Conrad, H., “Grain Size Dependence of the Flow Stress of Metals from Millimeters to Nanometers”, Metall. and Mater. Trans. A (2004) in print.Google Scholar
7. Armstrong, R.W. and Smith, T.R., in Processing and Properties of Nanocrystalline Materials, edited by Suryanarayana, C., Singh, J. and Froes, F.H., (TMS, Warrendale, PA, 1996), p. 345.Google Scholar
8. Li, J.C.M. and Liu, G.C.T., Philos. Mag. 15, 1059 (1967).Google Scholar
9. Armstrong, R.W., in Yield, Flow and Fracture of Polycrystals, edited by Baker, T.N. (Applied Science Publishers, Ltd., NY, 1983) p. 1.Google Scholar
10. Conrad, H. and Narayan, J., Acta Mater. 50, 5067 (2002).Google Scholar
11. Armstrong, R.W., in Ultrafine-Grain Metals, Sixteenth Sagamore Army Materials Research Conference, edited by Burke, J.J. and Weiss, V., (Syracuse Univ. Press, NY, 1970) p. 1.Google Scholar
12. Nabarro, F.R.N., Soviet Physics – Solid State Physics 42, 1417 (2000).Google Scholar
13. Van Swygenhoven, H., Spaczer, M., and Caro, A., Acta Mater. 47, 3117 (1999).Google Scholar
14. Armstrong, R.W. and Hughes, G.D., in Advanced Materials for the 21st Century: Julia R. Weertman Symposium, edited by Chung, Y.W., Dunand, D.C., Liaw, P.K. and Olson, G.B., (TMS, Warrendale, PA, 1999) p. 409.Google Scholar
15. Chen, M., Ma, E., Hemker, K.J., Sheng, H., Wang, Y. and Cheng, X., Science 300, 1275 (2003).Google Scholar
16. Armstrong, R.W., in Deformation Twinning, Metallurgical Society Conference Volume 25, edited by Reed-Hill, R.E., Hirth, J.P. and Rogers, H.C. (Gordon and Breach Science Publishers, NY, 1964) p. 356.Google Scholar
17. Wyrzykowski, J.W. and Grabski, M.W., Philos. Mag. A 53, 505 (1986).Google Scholar
18. Conrad, H., Acta Metall. 6, 339 (1958).Google Scholar
19. Armstrong, R.W., in Dislocation Dynamics, edited by Rosenfield, A.R., Hahn, G.T., Bement, A.L. Jr, and Jaffee, R.I., (McGraw-Hill Book Company, NY, 1968) p. 293.Google Scholar