Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-28T01:08:05.045Z Has data issue: false hasContentIssue false
  • English
  • Français

Cleavage fracture in an Al3Ti-based alloy having the Ll2 structure

Published online by Cambridge University Press:  31 January 2011

E. P. George ,
W. D. Porter ,
H. M. Henson ,
W. C. Oliver  and
B. F. Oliver
E. P. George
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831
W. D. Porter
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831
H. M. Henson
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831
W. C. Oliver
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831
B. F. Oliver
Affiliation:
Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200
Get access

Abstract

Selected area electron channeling patterns were used to identify the cleavage planes in a polycrystalline Al–23Ti–6Fe–5V alloy, which is an Al3Ti-based alloy having the Ll2 structure. Alloys like this one are of scientific and technological interest because they fracture by brittle transgranular cleavage, despite the availability of more than five independent slip systems in the Ll2 structure and their relatively low hardness when compared to ductile Ll2 alloys like Ni3Al. Homogenized bars of the levitation zone melted and directionally solidified alloy were fractured at room temperature in three point bending. The fracture surfaces, which consisted almost entirely of brittle transgranular cleavage facets, were examined in a scanning electron microscope (SEM) equipped to take channeling patterns. An optical microscope with a short depth of focus was inserted in the SEM column just below the objective lens, and by focusing it on several points on the cleavage facets, it was possible to orient the facets normal to the optic axis of the SEM prior to taking the channeling patterns. Of the eight cleavage facets examined in this study, six were of the {110} type and two were of the {111} type. Although it cannot be said that these are the only two cleavage planes in this alloy, the availability of more than one plane with low cleavage strength contributes to the brittleness of this alloy. These results are examined in the light of theoretical treatments of cleavage fracture, and comparisons are made with earlier studies on other Ll2 materials.

Type
Articles
Information
Journal of Materials Research , Volume 4 , Issue 1 , February 1989 , pp. 78 - 84
Copyright
Copyright © Materials Research Society 1989

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.)

References

REFERENCES

1Murray, J. L., in Binary Alloy Phase Diagrams, edited by Massalski, T. B., Murray, J. L., Bennett, L. H., and Baker, H. (American Society for Metals, Metals Park, OH, 1986), Vol. 1, p. 175.Google Scholar
2Villars, P. and Calvert, L. D., Pearson's Handbook of Crystallographic Data for Intermetallic Phases (American Society for Metals, Metals Park, OH, 1985), Vol. 1, p. 476.Google Scholar
3Yamaguchi, M., Umakoshi, Y., and Yamane, T., in High Temperature Ordered Intermetallic Alloys II (Proc. Mat. 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
4Liu, C.T., Int. Met. Rev. 29, 168 (1984).CrossRefGoogle Scholar
5Raman, A. and Schubert, K., Zeitschrift fur Metallkunde. 56, 99 (1965).Google Scholar
6Seibold, A., Zeitschrift für Metallkunde. 72 (1981).Google Scholar
7Huang, S.C., Hall, E. L., and Gigliotti, M.F.X., J. Mater. Res. 3, 1 (1988).CrossRefGoogle Scholar
8Tarnacki, J. and Kim, Y-W., Scripta Metall. 22, 329 (1988).CrossRefGoogle Scholar
9Porter, W. D. and Oliver, W. C., presented at the TMS-AIME Annual Meeting, Phoenix, AZ (1988).Google Scholar
10Porter, W.D. and Oliver, W.C., Oak Ridge National Laboratory (1988) (unpublished research).Google Scholar
11Oliver, B.F., Trans. AIME 227, 960 (1963).Google Scholar
12Hanada, S., Kim, M. S., Watanabe, S., and Izumi, O., Scripta Metall. 21, 277 (1987).CrossRefGoogle Scholar
13Joy, D. C., Newbury, D. E., and Davidson, D. L., J. Appl. Phys. 53, R81 (1982).CrossRefGoogle Scholar
14Hondros, E. D. and McLean, D., in Grain Boundary Structure and Properties, edited by G. A. Chadwick and D. A. Smith (Academic Press, London, 1976), p. 353.Google Scholar
15Mills, B., McLean, M., and Hondros, E. D., Phil. Mag. 27, 361 (1973).CrossRefGoogle Scholar
16Jokl, M.L., Vitek, V., and McMahon, C. J., Jr., Acta Metall. 28, 1479 (1980).CrossRefGoogle Scholar
17MacMillan, N. H., in Atomistics of Fracture, edited by Latanision, R. M. and Pickens, J. R. (Plenum Press, New York, 1983), p. 95.CrossRefGoogle Scholar
18Knott, J. F., ibid., p. 209.Google Scholar
19Ayres, R. and Stein, D. F., Acta Metall. 19, 789 (1971).CrossRefGoogle Scholar
20McLean, D., Grain Boundaries in Metals (Oxford University Press, London, 1957), p. 299.Google Scholar
21McMahon, C.J. Jr, . and V. Vitek, Acta Metall. 27, 509 (1979).Google Scholar
22Chen, 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
23Honeycombe, R. W. K., The Plastic Deformation of Metals (Edward Arnolds, London, 1984), p. 438.Google Scholar
24Aoki, A. and Izumi, O., Acta Metall. 27, 807 (1979).CrossRefGoogle Scholar
25Aoki, A. and Izumi, O., J. Mater. Sci. 14, 1800 (1979).CrossRefGoogle Scholar