Hostname: page-component-77c89778f8-n9wrp Total loading time: 0 Render date: 2024-07-23T09:32:00.910Z Has data issue: false hasContentIssue false
  • English
  • Français

Review of Environmental Effects in Intermetallics

Published online by Cambridge University Press:  22 February 2011

E. P. George  and
C. T. Liu
E. P. George
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6093
C. T. Liu
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6093
Get access

Abstract

The recent progress made in our understanding of the phenomenology and mechanisms of environmental embrittlement in ordered intermetallics is reviewed by considering two model alloy systems of the L12 and B2 crystal classes (Ni3Al and FeAl). The poor ductility commonly encountered when these alloys are tensile tested in ambient air is due mainly to environmental embrittlement, in the absence of which, both alloys are now known to be quite ductile. Both H2O and H2, at levels found in ordinary ambient air, are found to cause environmental embrittlement, with the former usually more deleterious. In the case of H2O, the micromechanism involves reaction with the intermetallic to form an oxide (or hydroxide) and simultaneous generation of atomic hydrogen which then enters the metal and causes embrittlement. In the case of H2, on the other hand, atomic hydrogen is generated as a result of the dissociation of physisorbed hydrogen molecules on the intermetallic surfaces. Consistent with the proposed embrittlement mechanism, ductility is found to increase with decreasing amounts of H2O (or H2) in the test environment, increasing strain rate, and decreasing (or increasing) temperature. Environmental embrittlement in Ni3Al (and other L12 alloys) occurs predominantly intergranularly, whereas in FeAl (and other B2 alloys) it can also occur transgranularly—presumably because diffusion of hydrogen is fast enough through the bulk in the more open B2 structure but only so along grain boundaries in the L12 structure. Microalloying with B, which segregates strongly to the grain boundaries, can overcome environmental embrittlement in L12 alloys, but not in B2 alloys; in the latter, alloying additions probably have to be added at significantly higher (macroalloy) levels to affect the bulk properties. In neither alloy is environmental embrittlement the sole source of brittleness: depending on the alloy stoichiometry, and grain boundary character, a given grain boundary may be intrinsically weaker (or stronger) than the bulk, thereby influencing overall ductility.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 364: Symposium L – High-Temperature Ordered Intermetallic Alloys–VI , 1994 , 1131
Copyright
Copyright © Materials Research Society 1995

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

1. Liu, C. T., Lee, E. H., and McKamey, C. G., Scripta. Metall. 23, 875 (1989).Google Scholar
2. Liu, C. T., in Ordered Intermetallics—Physical Metallurgy and Mechanical Behavior, edited by Liu, C. T., Cahn, R. W., and Sauthoff, G. (Kluwer Academic Publ., Netherlands, 1992) p. 321.Google Scholar
3. Stoloff, N. S. and Liu, C. T., Intermetallics, 2, 75 (1994).Google Scholar
4. Flinn, P. A., Trans. AIME, 218, 145 (1960).Google Scholar
5. Davies, R. G. and Stoloff, N. S., Trans. AIME, 233, 714 (1965).Google Scholar
6. Copley, S. M. and Kear, B. H., Trans. TMS-AIME, 239, 977 (1967).Google Scholar
7. Aoki, K. and Izumi, O., Trans. Jpn. Inst. Met. 19, 203 (1978).Google Scholar
8. Heredia, F. E. and Pope, D. P., Acta Metall. 39, 2017 (1991).Google Scholar
9. Davies, R. G. and Stoloff, N. S., Trans. TMS-AIME, 233, 714 (1965).Google Scholar
10. Thornton, P. H., Davies, R. G., and Johnston, T. L., Metall. Trans. 1, 207 (1970).Google Scholar
11. Aoki, K. and Izumi, O., Nippon Kinzoku Gakkaishi, 41, 170 (1977).Google Scholar
12. Liu, C. T., White, C. L., and Horton, J. A., Acta Metall. 33, 213 (1985).Google Scholar
13. Takasugi, T., George, E. P., Pope, D. P., and Izumi, O., Scripta Metall. 19, 551 (1985).Google Scholar
14. Ogura, T., Hanada, S., Masumoto, T., and Izumi, O., Metall. Trans. 16A, 441 (1985).Google Scholar
15. Takasugi, T. and Izumi, O., Acta Metall. 33, 1247 (1985).Google Scholar
16. Taub, A. I. and Briant, C. L., Acta Metall. 35, 1597 (1987).Google Scholar
17. King, A. H. and Yoo, M. H., in MRS Symp. Proc. Vol. 81 (1987) p. 99.Google Scholar
18. Kruisman, J. J., Vitek, V., De Hosson, J. T. M., Acta Metall. 36, 2729 (1988).Google Scholar
19. Liu, C. T. and George, E. P., Scripta Metall. 24, 1285 (1990).Google Scholar
20. Liu, C. T., McKamey, C. G., and Lee, E. H., Scripta. Metall. 24, 385 (1990).Google Scholar
21. Takasugi, T., Masahashi, N., and Izumi, O., Scripta Metall. 20, 1317 (1986).Google Scholar
22. Masahashi, N., Takasugi, T., and Izumi, O., Metall. Trans. 19A, 353 (1988).Google Scholar
23. Liu, C. T., Scripta Metall. Mater. 27, 25 (1992).Google Scholar
24. George, E. P., Liu, C. T., and Pope, D. P., Scripta Metall. Mater. 27, 365 (1992).Google Scholar
25. George, E. P., Liu, C. T., and Pope, D. P., Scripta Metall. Mater. 28, 857 (1993).Google Scholar
26. George, E. P., Liu, C. T., and Pope, D. P., Scripta Metall. Mater. 30, 37 (1994).Google Scholar
27. Cohron, J. and George, E. P., unpublished research, Oak Ridge National Laboratory (1994).Google Scholar
28. Handbook of Chemistry and Physics, 54th edition, CRC Press, Cleveland, OH (1973).Google Scholar
29. Chiba, A., Hanada, S., Watanabe, S., Abe, T., and Obana, T., Acta Metall. Mater. 42, 1733 (1994).Google Scholar
30. Hanada, S., Watanabe, S., and Izumi, O., J. Mater. Sci. 21, 203 (1986).Google Scholar
31. Lin, H. and Pope, D. P., Acta Metall. 41, 553 (1993).Google Scholar
32. Nishimura, C., Hirano, T., and Amano, M., Scripta Metall. Mater. 29 (1993).Google Scholar
33. George, E. P., unpublished research, Oak Ridge National Laboratory (1994).Google Scholar
34. Liu, C. T., Fu, C. L., George, E. P., and Painter, G. S., ISIJ Intl. 31, 1192 (1991).Google Scholar
35. Li, J. C. M. and Liu, C. T., submitted to Acta Metall. Mater. (1994).Google Scholar
36. Taub, A. I., Chang, K. -M., and Liu, C. T., Scripta Metall. 20, 1613 (1986).Google Scholar
37. Liu, C. T. and Sikka, V. K., J. Met. 38, 19 (1986).Google Scholar
38. White, C. L. and Stein, D. F., Metall. Trans. 9A, 113 (1978).Google Scholar
39. Aoki, K. and Izumi, O., Nippon Kinzoku Gakkaishi 43, 1190 (1979).Google Scholar
40. Taub, A. I., Huang, S. C., and Chang, K. M., Metall. Trans. 15A, 399 (1984).Google Scholar
41. Hirano, T., Acta Metall. 38, 2667 (1990).Google Scholar
42. Hirano, T., Scripta Metall. 25, 1747 (1991).Google Scholar
43. Hirano, T., Chung, S. S., Mishima, Y., and Suzuki, T., in MRS Symp. Proc. Vol. 213 (1991) p. 635.Google Scholar
44. Horton, J. A. and Miller, M. K., Acta Metall. 35, 133 (1987).Google Scholar
45. Schulson, E. M., Wiehs, T. P., Viens, D. V., and Baker, I., Acta Metall. 33, 1587 (1985).Google Scholar
46. Liu, C. T., Scripta Metall. Mater. 25, 1231 (1991).Google Scholar
47. Vitek, V. and Chen, S. P., Scripta Metall. Mater. 25, 1237 (1991).Google Scholar
48. Takasugi, T. and Izumi, O., Scripta Metall. Mater. 25, 1243 (1991).Google Scholar
49. King, A. H., Frost, H. J., and Yoo, M. H., Scripta Metall. Mater. 25, 1249 (1991).Google Scholar
50. Schulson, E. M. and Baker, I., Scripta Metall. Mater. 25, 1253 (1991).Google Scholar
51. George, E. P., White, C. L., and Horton, J. A., Scripta Metall. Mater. 25, 1259 (1991).Google Scholar
52. Lee, T. C., Subramanian, R., Robertson, I. M., and Birnbaum, H. K., Scripta Metall. Mater. 25, 1265 (1991).Google Scholar
53. Brenner, S. S. and Hua, M. -G., Scripta Metall. Mater. 25, 1271 (1991).Google Scholar
54. Kung, H., Rasmussen, D. R., and Sass, S. L., Scripta Metall. Mater. 25, 1277 (1991).Google Scholar
55. Mills, M. J., Goods, S. H., Foiles, S. M., and Whetstone, J. R., Scripta Metall. Mater. 25, 1283 (1991).Google Scholar
56. Liu, C. T., unpublished research, Oak Ridge National Laboratory (1994).Google Scholar
57. Wan, X. J., Zhu, J. H., Jing, K. L., and Liu, C. T., Scripta Metall. Mater. 31, 677 (1994).Google Scholar
58. Kuruvilla, A. K. and Stoloff, N. S., Scripta Metall. 19, 83 (1985).Google Scholar
59. Chen, S. P., Voter, A. F., Albers, R. C., Boring, A. M., and Hay, P. J., Scripta Metall. 23, 217 (1989).Google Scholar
60. Mackenzie, R. A. D., Vaudin, M. D., and Sass, S. L., in MRS Symp. Proc. Vol. 122 (1988) p. 461.Google Scholar
61. Farkas, Diana, Jang, H., Lewus, M. O., Versaci, R., and Savino, E. J., in MRS Symp. Proc. Vol. 122 (1988) p. 455.Google Scholar
62. Takasugi, T., Izumi, O., and Masahashi, N., Acta Metall. 33, 1259 (1985).Google Scholar
63. Masahashi, N., Takasugi, T., and Izumi, O., Acta Metall. 36, 1823 (1988).Google Scholar
64. Chiba, A., Hanada, S., and Watanabe, S., Acta Metall. 39, 1799 (1991).Google Scholar
65. Chiba, A., Hanada, S., and Watanabe, S., Scripta Metall. 25, 1053 (1991).Google Scholar
66. Chiba, A., Hanada, S., and Watanabe, S., Scripta Metall. 25, 303 (1991).Google Scholar
67. Chiba, A., Hanada, S., and Watanabe, S., Mater. Sci. Engg. A152, 108 (1992).Google Scholar
68. Aoki, K., Mater. Trans. JIM 31, 443 (1990).Google Scholar
69. George, E. P., Liu, C. T., and Pope, D. P., in Structural Intermetallics (eds. Darolia, R., Lewandowski, J. J., Liu, C. T., Martin, P. L., Miracle, D. B., and Nathal, M. V.) TMS, Warrendale, PA (1993) p. 431.Google Scholar
70. Dimiduk, D. M., Weddington, V. L., and Lipsitt, H. A., in MRS Symp, Proc. Vol. 81 (1987) p. 221.Google Scholar
71. Liu, C. T. and George, E. P., in MRS Symp. Proc. Vol. 213 (1991) p. 527.Google Scholar
72. Gaydosh, D. J., Draper, S. L., and Nathal, M. V., Metall Trans. 20A, 1701 (1989).Google Scholar
73. Crimp, M. A. and Vedula, K. M., Mater. Sci. Eng. 78, 193 (1986).Google Scholar
74. Baker, I. and Gaydosh, D. J., Mater. Sci. Eng. 96, 147 (1987).Google Scholar
75. Kerr, W. R., Metall. Trans. 17A, 2298 (1986).Google Scholar
76. Morgund, P., Moururat, P., and Sainfort, G., Acta Metall. 16, 867 (1968).Google Scholar
77. Causey, A. and Teghtsoonian, E., Metall. Trans. 1, 1177 (1970).Google Scholar
78. Crimp, M. A., Vedula, K. M., and Gaydosh, D. J., in MRS Symp. Proc. Vol. 81 (1987) p. 499.Google Scholar
79. Lin, Y. and George, E. P., unpublished research, Oak Ridge National Laboratory (1994).Google Scholar
80. Liao, J. J. and George, E. P., unpublished research, Oak Ridge National Laboratory (1994).Google Scholar
81. Baker, I., Klein, O., Nelson, C., and George, E. P., Scripta Metall. Mater. 30, 863 (1994).Google Scholar
82. Schneibel, J. H., Jenkins, M. G., and Maziasz, P. J., in MRS Proc. Symp. Vol. 288 (1993) p. 549.Google Scholar
83. Schneibel, J. H. and Jenkins, M. G., Scripta Metall. Mater. 28, 389 (1993).Google Scholar
84. Schneibel, J. H., George, E. P., Specht, E., and Horton, J. A., in these proceedings.Google Scholar
85. George, E. P., Liu, C. T., Lin, H. and Pope, D. P., Mater. Sci. Eng. (1995), in press.Google Scholar