Abstract
Computer simulation of the core structure and glide of ordinary 1/2<110] dislocations and <101] superdislocations in L10 TiAl has been performed using the recently constructed BondOrder Potentials. This description of atomic interactions includes explicitly, within the tight-binding approximation, the most important aspects of the directional bonding, namely d-d, p-p and d-p bonds. The ordinary dislocation in the screw orientation was found to have a non-planar core and, therefore, high Peierls stress. The superdislocation was found to possess in the screw orientation either a planar (glissile) or a non-planar (sessile) core structure. However, the glissile core transforms into the sessile one for certain orientations of the applied stress. This implies a strong asymmetry of the yield stress and the break down of the Schmid law when the plastic flow is mediated by superdislocations. At the same time, this may explain the orientation dependence of the dislocation substructure observed in the single-phase γ-TiAl by electron microscopy.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
M. Yamaguchi, H. Inui, S. Yokoshima, K. Kishida and D. R. Johnson, Mat. Sci. Eng. A 213, 25 (1996).
S. Sriram, V. K. Vasudevan and D. Dimiduk, High-Temperature Ordered Intermetallic Alloys VI, edited by J. A. Horton, I. Baker, S. Hanada, R. D. Noebe and D. S. Schwartz (Pittsburgh, Materials Research Society), Vol. 364, p. 647 ( 1999).
H. Inui, M. Matsumuro, D. H. Wu and M. Yamaguchi, Philos. Mag. A 75, 395 (1997).
T. Kawabata, T. Kanai and O. Izumi, Acta Metall. 33, 1355 (1985).
M. S. Duesbery, Dislocations in Solids, edited by F. R. N. Nabarro (Amsterdam, Elsevier), Vol. 8, p. 67 ( 1989).
V. Vitek, Prog. Mater. Sci. 36, 1 (1992).
V. Vitek, Intermetallics 6, 579 (1998).
A. Girshick and V. Vitek, High-Temperature Ordered Intermetallic Alloys VI, edited by J. Horton, I. Baker, S. Hanada, R. D. Noebe and D. Schwartz (Pittsburgh, Materials Research Society), Vol. 364, p. 145 ( 1995).
J. P. Simmons, S. I. Rao and D. M. Dimiduk, Philos. Mag. A 75, 1299 (1997).
J. Panova and D. Farkas, Philos. Mag. A 78, 389 (1998).
C. Woodward and S. I. Rao, Philos. Mag. A, in press (2003).
Y. Song, S. P. Tang, J. H. Xu, O. N. Mryasov, A. J. Freeman, C. Woodward and D. M. Dimiduk, Philos. Mag. B 70, 987 (1994).
N. Nguyen-Manh, A. M. Bratkovsky and D. G. Pettifor, Phil. Trans. Roy. Soc. London A 351, 529 (1995).
J. Zou, C. L. Fu and M. H. Yoo, Intermetallics 3, 265 (1995).
D. Nguyen-Manh and D. G. Pettifor, Intermetallics 7, 1095 (1999).
D. Nguyen-Manh and D. G. Pettifor, Gamma Titanium Aluminides, edited by Y. W. Kim (Pittsburgh, TMS), p. 175 ( 1999).
S. Znam, Philadelphia, University of Pennsylvania, (2001).
S. Znam, D. Nguyen-Manh, D. G. Pettifor and V. Vitek, Philos. Mag. A, in press (2003).
D. G. Pettifor, Phys. Rev. Lett. 63, 2480 (1989).
A. P. Horsfield, A. M. Bratkovsky, M. Fearn, D. G. Pettifor and M. Aoki, Phys. Rev. B 53, 1656, 12694 (1996).
D. G. Pettifor, I. I. Oleinik, D. Nguyen-Manh and V. Vitek, Comp. Mat. Sci. 23, 33 (2002).
V. Vitek, K. Ito, R. Siegl and S. Znam, Mat. Sci. Eng. A 240, 752 (1997).
J. Ehmann and M. Fähnle, Philos. Mag. A 77, 701 (1998).
F. Gregori and P. Veyssiere, Philos. Mag. A 80, 2913, 2933 (2000).
K. Ito and V. Vitek, Philos. Mag. A 81, 1387 (2001).
S. I. Rao and C. Woodward, Philos. Mag. A 81, 1317 (2001).
C. Woodward and S. I. Rao, Philos. Mag. A 81, 1305 (2001).
P. Veyssiere, Y.-L. Chiu and F. Gregori, Defect Properties and Related Phenomena in Intermetallic Alloys, edited by E. P. George, M. J. Mills, H. Inui and G. Eggeler, this volume ( 2003).
G. Hug, A. Loiseau and P. Veyssiere, Philos. Mag. A 57, 499 (1988).
Z. X. Li and S. H. Whang, Mat. Sci. Eng. A 152, 182 (1992).
H. Inui and M. Yamaguchi, Electron Microscopy 32,144 (1997).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Porizek, R., Znam, S., Nguyen-Manh, D. et al. Atomistic Studies of Dislocation Glide in γ-TiAl. MRS Online Proceedings Library 753, 43 (2002). https://doi.org/10.1557/PROC-753-BB4.3
Published:
DOI: https://doi.org/10.1557/PROC-753-BB4.3