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Tailoring the thermal expansion anisotropy of Mo5Si3

Published online by Cambridge University Press:  21 March 2011

Joachim H. Schneibel ,
Claudia J. Rawn  and
Chong Long Fu
Joachim H. Schneibel
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A.
Claudia J. Rawn
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A.
Chong Long Fu
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A.
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Abstract

The silicide Mo5Si3, with the W5Si3 structure, exhibits a high anisotropy of its coefficients of thermal expansion (CTEs) in the a and c directions, namely, CTE(c)/CTE(a)=2.2. In order to determine whether the CTE anisotropy can be controlled, molybdenum was partially substituted with Nb. CTEs were determined by high temperature x-ray powder diffraction. Partial substitution with 44 at. % Nb reduced the value of CTE(c)/CTE(a) to a value near 1. For higher Nb concentrations, CTE(c)/CTE(a) increased again. When nearly all the Mo was replaced by Nb, the crystal structure changed to the Cr5B3 structure type and the CTE anisotropy decreased to a value near 1. Our thermal expansion results are interpreted in terms of the site occupation of Nb, the Nb-induced increase in the interatomic spacing of the Mo atom chains along the c-direction, and the reduction in the anisotropy of the lattice anharmonicity in the a and c directions.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 646 , 2000 , N5.40.1
Copyright
Copyright © Materials Research Society 2001

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References

REFERENCES

1. Vasudevan, A. K. and Petrovic, J. J., Materials Science & Engineering A261, 1 (1999).Google Scholar
2. Meyer, M. K., Kramer, M. J., and Akinca, M. [sic], Intermetallics 4, 273 (1996).Google Scholar
3. Akinc, M., Meyer, M. K., Kramer, M. J., Thom, A. J., Huebsch, J. J., and Cook, B., Materials Science and Engineering A261, 16 (1999).Google Scholar
4. Chu, F., Thoma, D. J., McClellan, K., Peralta, P., and He, Y., Intermetallics 7, 611 (1999).Google Scholar
5. Schneibel, J. H., Liu, C. T., Heatherly, L., and Kramer, M. J., Scripta Mater. 38 [7], 1169 (1998).Google Scholar
6. Fu, C. L., Wang, X., Ye, Y. Y., and Ho, K. M., Intermetallics 7, 179 (1999).Google Scholar
7. Fu, C. L. and Wang, X., Phil. Mag. Ltr. 80, 683 (2000).Google Scholar
8. Ikarashi, Y., Ishizaki, K., Nagai, T., Hashizuka, Y., and Kondo, Y., Intermetallics 4, S141 (1996).Google Scholar
9. Touloukian, Y. S. (Ed.), Thermophysical Properties of High Temperature Solid Materials, Macmillan, NewYork, 1967.Google Scholar
10. Fu, C. L., Schneibel, J. H., and Rawn, C. J., these proceedings.Google Scholar
11. Rawn, C. J., Schneibel, J. H., Hoffmann, C. M., and Hubbard, C. R., The Crystal Structure and Thermal Expansion of Mo5SiB2 , in press.Google Scholar