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The Yield Stress Anomaly in Ll2 Alloys

Published online by Cambridge University Press:  01 January 1992

Peter B. Hirsch
Peter B. Hirsch*
Affiliation:
University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH, England.
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Abstract

The implications of the basic assumptions of the local pinning theories for the yield stress anomaly in Ll2 alloys are discussed. An alternative theory is presented in which the superpartials on (111) cross-slip on to (010) to form long locks lying partially on (111) and (010) or completely on (010) planes (Kear-Wilsdorf locks). The ends of the locks are joined by glissile superkinks. The yield stress is controlled by superkinks bypassing the screw dislocation locks, and the increase of the yield stress with increasing temperature is due to the decrease of the lengths of superkinks. The theory accounts satisfactorily for the mechanical properties including the small strain-rate dependence of the yield stress and is consistent with electron microscope observations.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 288: Symposium L – High-Temperature Ordered Intermetallic Alloys V , 1992 , 33
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

[1] Takeuchi, S. and Kuramoto, E., Acta Metall., 21, 415 (1973)Google Scholar
[2] Paidar, V., Pope, D.P. and Vitek, V., Acta Metall., 32, 435 (1984)Google Scholar
[3] Vitek, V. and Sodani, Y., Scripta Metall Mater., 25, 939 (1991)Google Scholar
[4] Khantha, M., Cserti, J. and Vitek, V., Scripta Metall Mater., 27, 481 (1992)Google Scholar
[5] Hirsch, P.B., Scripta Metall. Mater., 25, 1725 (1991)Google Scholar
[6] Hirsch, P.B., Phil. Mag. A, 65, 569 (1992)Google Scholar
[7] Hirsch, P.B., Progr. Mats. Sci., 36, 63 (1992)Google Scholar
[8] Millls, M.J., Chrzan, D.C., Hemker, K.J. and Nix, W.D., in Modelling the Deformation in Crystalline Solids, Eds. Lowe, T. and Rollett, R., TMS Publ. 0423 (1991).Google Scholar
[9] Flinn, P., Trans. TMS-A1ME, 218, 145 (1960)Google Scholar
[10] Yoo, M.H., Scripta Metall, 20, 915 (1986)Google Scholar
[11] Thornton, P.H., Davies, R.G. and Johnston, T.L., Metall. Trans., 1, 207 (1970)Google Scholar
[12] Hirsch, P.B., J. de Phys. III, 1, 989 (1991).Google Scholar
[13] Molénat, G. and Caillard, D., Phil. Mag. A, 64, 1291 (1991).Google Scholar
[14] Bonneville, J., Baluc, N. and Martin, J.L. in Int'l Symp. on Intermetallic Compounds - Structure and Mechanical Properties, JIMIS-6, p323, edited by Izumi, O. (The Japan Institute of Metals).Google Scholar
[15] Mills, M.J., Baluc, N. and Karnthaler, H.P. in High Temperature Ordered Intermetallics III, edited by Kock, C.C., Liu, C.T., Stoloff, N.S. and Taub, A.I., p203 (MRS Proc., 133, 1989).Google Scholar
[16] Veyssière, P. in High Temperature Ordered Intermetallics III, edited by Kock, C.C., Liu, C.T., Stoloff, N.S. and Taub, A.I., pl75 (MRS Proc., 133, 1989).Google Scholar
[17] Sun, Y.Q. and Hazzledine, P.M., Phil. Mag. A, 58, 603 (1988).Google Scholar
[18] Sun, Y.Q., D. Phil thesis, University of Oxford (1990).Google Scholar
[19] Hirsch, P.B. and Lothe, J., Teory of Dislocations, 1st Ed. (McGraw-Hill, New-York 1968) p493.Google Scholar
[20] Davies, R.G. and Stoloff, N.S., Trans. TMS AIME, 233, 714 (1965).Google Scholar
[21] Dimiduk, D.M., D. Phil thesis, Carnegie-Mellon University (1989).Google Scholar
[22] Chou, C.T. and Hirsch, P.B., Phil. Mag., 44, 1415 (1981).Google Scholar
[23] Couret, A., Sun, Y.Q. and Hirsch, P.B., Phil. Mag. (1992), in press.Google Scholar
[24] Umakoshi, Y., Pope, D.P. and Vitek, V., Acta Metall., 32, 449 (1984).Google Scholar
[25] Neveu, C., D. Phil thesis, University of Paris-Sud (1991).Google Scholar
[26] Douin, J., Veyssière, P. and Beauchamp, P., Phil. Mag., A54, 375 (1986).Google Scholar
[27] Baluc, N., Schaublin, R. and Hemker, K.J., Phil. Mag. Lett., 64, 327 (1991).Google Scholar
[28] Heredia, F.E. and Pope, D.P., J. de Phys. III, 1 (6), 1055 (1991).Google Scholar
[29] Heredia, F.E. and Pope, D.P., Acta. Metall. Mater., 39, 2027 (1991).Google Scholar
[30] Curwick, L.R., D. Phil thesis, University of Minnesota (1972).Google Scholar
[31] Mills, M.J. and Chrzan, D.C., Acta. Metall. Mater., 40, 3051 (1992).Google Scholar