Hostname: page-component-5b777bbd6c-7sgmh Total loading time: 0 Render date: 2025-06-21T19:37:37.469Z Has data issue: false hasContentIssue false
  • English
  • Français

Brittle cleavage of L12 trialuminides

Published online by Cambridge University Press:  31 January 2011

E. P. George ,
J. A. Horton ,
W. D. Porter  and
J. H. Schneibel
E. P. George
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6093
J. A. Horton
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6093
W. D. Porter
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6093
J. H. Schneibel
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6093
Get access

Abstract

Three trialuminide alloys, binary Al–25Sc, ternary Al–25Zr–6Fe, and quaternary Al–23Ti–6Fe–5V, all having the cubic L12 structure, were investigated. All three alloys fracture in a brittle manner (fracture toughness, 2–3 MPa m½), predominantly by transgranular cleavage. Of nineteen cleavage facets examined in binary Al3Sc, seventeen were of the {110} type and only two were of the {100} type, consistent with our earlier work which showed that the cleavage plane occurring most frequently in quaternary Al–23Ti–6Fe–5V is also {110}. The room-temperature hardnesses and yield strengths (100–200 DPH and 100–270 MPa, respectively) of all three alloys are quite low (comparable to ductile L12 alloys like Ni3Al), indicating that there is significant dislocation activity in these materials. Consistent with this, transmission electron microscopy identified several APB-coupled dislocations with b - a/2〈110〉 gliding on the {111} planes in both binary Al–25Sc and quaternary Al–23Ti–6Fe–5V. The separations between the superpartials in Al–25Sc and Al–23Ti–6Fe–5V were measured to be 3.7 and 4 nm, respectively, giving APB energies of 313 and 274 mJ/m2, respectively. Auger analyses failed to detect any impurities on the cleavage facets themselves, or on second phase particles (or other potential cleavage crack nucleation sites). It is therefore concluded that brittle fracture in these alloys is not impurity-induced. Based on all the results obtained to date we conclude that the unusual brittleness of L12 trialuminides is related to their intrinsically low cleavage strength. Possible reasons for their low cleavage strength are discussed.

Type
Articles
Information
Journal of Materials Research , Volume 5 , Issue 8 , August 1990 , pp. 1639 - 1648
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

1Zedalis, M. S., Ghate, M. V., and Fine, M. E., Scripta Metall. 19, 647 (1985).CrossRefGoogle Scholar
2Yamaguchi, M., Umakoshi, Y., and Yamane, T., Philos. Mag. A 55, 301 (1987).Google Scholar
3Yamaguchi, M., Umakoshi, Y., and Yamane, T., in High Temperature Ordered Intermetallic Alloys II (Proc. Mater. Res. Soc. Symp.), edited by Stoloff, N. S., Koch, C. C., Liu, C. T., and Izumi, O. (Materials Research Society, Pittsburgh, PA, 1987), Vol. 81, p. 275.Google Scholar
4Umakoshi, Y., Yamaguchi, M., Yamane, T., and Hirano, T., Philos. Mag. A 58, 651 (1988).Google Scholar
5Kumar, K. S. and Pickens, J. R., Scripta Metall. 22, 1015 (1988).Google Scholar
6Tarnacki, J. and Kim, Y-W., Scripta Metall. 22, 329 (1988).CrossRefGoogle Scholar
7Huang, S. C., Hall, E. L., and Gigliotti, M. F. X., J. Mater. Res. 3 (1), 1 (1988).Google Scholar
8Schneibel, J. H., Becher, P. F., and Horton, J. A., J. Mater. Res. 3 (6), 1272 (1988).Google Scholar
9George, E. P., Porter, W. D., Henson, H. M., Oliver, W. C., and Oliver, B. F., J. Mater. Res. 4 (1), 78 (1989).CrossRefGoogle Scholar
10George, E. P., Porter, W. D., and Joy, D. C., in High Temperature Ordered Intermetallic Alloys III (Proc. Mater. Res. Soc. Symp.), edited by Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. (Materials Research Society, Pittsburgh, PA, 1989), Vol. 133, p. 311.Google Scholar
11Porter, W. D., Hisatsune, K., Sparks, C. J., Oliver, W. C., and Dhere, A., in High Temperature Ordered Intermetallic Alloys III (Proc. Mater. Res. Soc. Symp.), edited by Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. (Materials Research Society, Pittsburgh, PA, 1989), Vol. 133, p. 657.Google Scholar
12Schneibel, J. H. and Porter, W. D., in High Temperature Ordered Intermetallic Alloys III (Proc. Mater. Res. Soc. Symp.), edited by Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. (Materials Research Society, Pittsburgh, PA, 1989), Vol. 133, p. 335.Google Scholar
13Vasudevan, V. K., Wheeler, R., and Fraser, H. L., in High Temperature Ordered Intermetallic Alloys III (Proc. Mater. Res. Soc. Symp.), edited by Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. (Materials Research Society, Pittsburgh, PA, 1989), Vol. 133, p. 705.Google Scholar
14Mazdiyasni, S., Miracle, D. B., Dimiduk, D. M., Mendiratta, M. G., and Subramanian, P. R., Scripta Metall. 23, 327 (1989).CrossRefGoogle Scholar
15Powers, W. O., Wert, J. A., and Turner, C. D., Philos. Mag. A 60, 227 (1989).Google Scholar
16Turner, C. D., Powers, W. O., and Wert, J. A., Acta Metall. (in press).Google Scholar
17Powers, W. O. and Wert, J. A., Philos. Mag. (in press).Google Scholar
18Powers, W. O. and Wert, J. A., Metall. Trans., accepted for publication.Google Scholar
19Mysko, D. D., Lumsden, J. B., Powers, W. O., and Wert, J. A., Scripta Metall., accepted for publication.Google Scholar
20Villars, P. and Calvert, L. D., Pearson's Handbook of Crystallographic Data for Intermetallic Phases (American Society for Metals, Metals Park, OH, 1985).Google Scholar
21Fu, C. L., J. Mater. Res. 5 (5), 971 (1990).CrossRefGoogle Scholar
22Nose, T. and Fujii, T., J. Am. Ceram. Soc. 71, 328 (1988).CrossRefGoogle Scholar
23Tada, H., Paris, P. C., and Irwin, G. R., The Stress Analysis of Cracks Handbook (Paris Production Inc. and Del Research Corporation, St. Louis, MO, 1985), 2nd ed.Google Scholar
24Nondestructive Testing Handbook, edited by McMaster, Robert C. (The Ronald Press Co., New York, 1959), Vol. 2, p. 43.Google Scholar
25Fager, D. N., Hyatt, M. V., and Diep, H. T., Scripta Metall. 20, 1159 (1986).CrossRefGoogle Scholar
26Miller, W. S., Thomas, M. P., and White, J., Scripta Metall. 21, 663 (1987).Google Scholar
27Chen, S. P., Voter, A. F., and Srolovitz, D. J., presented at the conference on “Interface Science and Engineering,” Lake Placid, New York, 1987, to be published in J. de Physique.Google Scholar
28Pugh, S. F., Philos. Mag. 45, 823 (1954).Google Scholar