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Atypical Defects in a B2 Fe-40A1–0.7C-0.5B Alloy

Published online by Cambridge University Press:  10 February 2011

L. Pang and
K. S. Kumar
L. Pang
Affiliation:
Division of Engineering, Brown University, Providence, RI 02912
K. S. Kumar
Affiliation:
Division of Engineering, Brown University, Providence, RI 02912
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Abstract

The nature of defects in a quaternary Fe-40A1–0.7C-0.5B alloy was examined by transmissionelectron microscopy (TEM) techniques including weak beam microscopy and z-contrast imaging.Complex {001} stacking faults were observed in certain conditions in these alloys that were not previouslynoted in a ternary Fe-40A1–0.6C alloy. These faults exhibit a 1/2<001> displacement vectorthat lies in the plane of the fault and structurally misses an aluminum layer. Six variants of this faulttype are present. These faults are absent in brine-quenched and furnace-cooled alloys, but are readilyobserved in the air-cooled condition. In addition to the usual <111> superdislocations that are APBdissociatedinto 1/2<111> superpartials, dissociated <100> dislocations (into two 1/2< 100> partials)are also observed under certain conditions. Quenched and aged alloys show dissociated <001> loops.The absence of such defects in the B-free alloy and following certain heat treatments in the B-containingalloy, suggests that boron may be segregating to the cube planes and lowering the interfacialenergy on these planes. The presence of dissociated <001> loops in the quenched and aged alloy alsosuggests the formation of B-vacancy complexes that coalesce during aging, forming such dissociatedloops.

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References

REFERENCES

1. Liu, C.T., Lee, E.H., and McKamey, C.G., Scripta Metall Mater., 23, 875 (1989).CrossRefGoogle Scholar
2. Liu, C.T., Mckamey, C.G., and Lee, E.H., Scripta Metall Mater., 24, 385 (1990).CrossRefGoogle Scholar
3. Gaydosh, D.J., and Nathal, M.V, Scripta Metall Mater., 24, 1281 (1990).CrossRefGoogle Scholar
4. Liu, C.T. and George, E.P., Scripta Metall Mater., 24, 1285 (1990).CrossRefGoogle Scholar
5. Liu, C.T. and George, E.P., in High Temperature Intermetallic Alloys IV, Vol.213, ed. Johnson, L.A., Pope, D.P. and Stiegler, J.O., Materials Rsearch Society, Pittsburgh, PA, 1991, p.527.Google Scholar
6. Stoloff, N.S., and Liu, C.T., Intermetallics, 2, 75 (1994).CrossRefGoogle Scholar
7. Crimp, M.A. and Vedula, K., Mater. Sci. and Eng., 78, 193 (1986).CrossRefGoogle Scholar
8. Crimp, M.A., Vedula, K.M., and Gaydosh, D.J., in High Temperature Ordered Intermetallic Alloys II, Vol.81, ed. Stoloff, N.S., Koch, C.C., Liu, C.T. and Izumi, O., Materials Rsearch Society, Pittsburgh, PA, 1987, p.409.Google Scholar
9. Gaydosh, D.J., Draper, S.L., and Nathal, M.V, Metall. Trans., 20A, 1701 (1989).CrossRefGoogle Scholar
10. Pike, L.M., and Liu, C.T., Scripta Metall. Mater., 25, 2757 (1991).CrossRefGoogle Scholar
11. Aoki, K. and Izumi, O., Nippon Kinzoku Takkaishi, 43, 1190 (1979).Google Scholar
12. Baker, I. and Munroe, P R., Inter. Mater. Rev., 42, 181 (1997).CrossRefGoogle Scholar
13. Fourdeux, A. and Lesbats, P., Philos. Mag. A, 45, 81 (1982).CrossRefGoogle Scholar
14. Song, Z. Y., Hasimoto, H., Chou, C.T. and Endoh, H., Philos. Mag. A, 64, 333 (1991).CrossRefGoogle Scholar
15. Yoshimi, K. and Hanada, S., Philos. Mag. A, 73, 443 (1996).CrossRefGoogle Scholar
16. Pang, L. and Kumar, K. S., Mater. Sci. and Eng., 1998 — in press.Google Scholar
17. Pang, L., Chisholm, M.E and Kumar, K.S., Philos. Mag. Lett..,78, 349 (1998).CrossRefGoogle Scholar
18. Pang, L. and Kumar, K.S., Acta Mater., 46, 4017 (1998).CrossRefGoogle Scholar
19. Kumar, K.S. and Pang, L., Mater. Sci. and Eng., 1998 — in press.Google Scholar
20. Pang, L. and Kumar, K. S., Philos. Mag. Lett., 76, 323 (1997).CrossRefGoogle Scholar
21. Pang, L. and Kumar, K.S., in Structural Intermetallics 1997, editors: Nathal, M.V et al., Conference Proceedings published by The Materials Society, Warrendale, PA, 1997, p. 703.Google Scholar