Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-03T08:26:21.626Z Has data issue: false hasContentIssue false

Impurity Effects on the Environmental Stability of Powder Processed Intermetallic Alumino-Silicide Compounds

Published online by Cambridge University Press:  03 March 2011

P.D. Eason*
Affiliation:
e4 Consulting, Inc., Jacksonville, Florida 32256
M.J. Kaufman
Affiliation:
University of North Texas, Department of Materials Science and Engineering, Denton, Texas 76203-5310
*
a)Address all correspondence to these authors. e-mail: [email protected]
Get access

Abstract

The evolution of nearly dense stoichiometric silicide compacts via powder processing is presented in this paper. For specific single-phase Mo(Si,Al)2 compacts, room-temperature environmental degradation, phenomenologically similar to the pesting behavior of binary MoSi2 was observed. This degradation occurs over a series of a few months and results in grain boundary decohesion, which leads to crumbling of polycrystalline compacts in air at room temperature. Auger electron spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy of the boundaries revealed the presence of an array of lens-shaped particles each comprised of silicon carbide and aluminum. The reaction of these phases with atmospheric species was accelerated by the presence of humidity. The trace presence of carbon was unavoidable due to the use graphite pressing dies. Alloying additions were made to tie up carbon by forming more stable carbides while maintaining the desired matrix phase stoichiometry. The pest phenomenon and alloying remedy were proven applicable to other silicide systems through experimentation and ThermoCalc modeling.

Type
Articles
Copyright
Copyright © Materials Research Society 2005

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

1Gokhale, A. and Abbaschian, G.J.: The Mo–Si (molybdenum silicon) system. J. Phase Equilibria 12, 493 (1991).CrossRefGoogle Scholar
2Samsonov, G.V. and Vinitskii, I.M.: Handbook of Refractory Materials (IFI Plenum, New York, 1980).Google Scholar
3Boettinger, W.J., Perepezko, J.H. and Frankwicz, P.S.: Application of ternary phase diagrams to the development of MoSi2-based materials. Mater. Sci. Eng. A155, 33 (1992).CrossRefGoogle Scholar
4Brukl, C.H., Nowotny, H. and Benesovsky, F.: Examination of the ternary systems: V–Al–Si, Nb–Al–Si, Cr–Al–Si, Mo–Si–Al BZW, Cr(Mo)–Al–Si. Chem. Monthly (German) 92, 965 (1961).Google Scholar
5Brukl, C.H., Nowotny, H., Schob, O. and Benesovsky, F.: The crystal structures of TiSi, Ti(Al,Si)2, and Mo(Si,Al)2. Chem. Monthly (German) 92, 779 (1961).Google Scholar
6Stergiou, A. and Tsakiropolous, P.: Study of the effects of Al, Ta, W additions on the microstructure and properties of MoSi2 based alloys, in High-Temperature Ordered Intermetallic Alloys VI, Part 2, edited by Horton, J.A., Baker, I., Hanada, D.S., Noebe, R.D., and Schwartz, D.S. (Mater. Res. Soc. Symp. Proc. 364, Pittsburgh, PA1995). pp. 911916.Google Scholar
7Shah, D.M., Berczick, D., Anton, D.L. and Hecht, R.: Appraisal of other silicides as structural materials. Mater. Sci. Eng. A A155, 45 (1992).Google Scholar
8Stergiou, A. and Tsakiropolous, P.: The intermediate and high temperature oxidation behaviour of (Mo,X)Si2 (X = W,Ta) intermetallic alloys. Intermetallics 5, 117 (1997).CrossRefGoogle Scholar
9Yanigahara, K., Maruyama, T. and Nagata, K.: High temperature oxidation of Mo–Si–X intermetallics (X = Al, Ti, Ta, Zr, Y). Intermetallics 3, 243 (1994).Google Scholar
10Ross, E.N., Eason, P.D., and Kaufman, M.J.: Processing of low silica MoSi2-based compounds using carbon and aluminum additions, in Processing and Fabrication of Advanced Materials V (Proceedings of TMS Annual Meeting, Warrendale, PA,1996), pp. 347360.Google Scholar
11Stergiou, A. and Tsakiropoulos, P.: Oxiaditon studies on MoSi2-X (X = Al,Ta,W) alloys. Struct. Intermetallics 5, 869 (1997).Google Scholar
12Yanigahara, K., Maruyama, T. and Nagata, K.: Isothermal and cyclic oxidation of Mo(Si1−X,AlX) up to 2048 K. Mater. Trans. JIM 34, 1200 (1993).Google Scholar
13Matsura, K., Ohmi, T., Kudoh, M., Kakuhashi, T. and Hasegawa, T.: Raective sintering of molybdenum alumino-silicide and its oxidation resistance. J. Jpn. Inst. Light Metals 47, 446 (1997).Google Scholar
14Silva, A. Costa e and Kaufman, M.J.: Microstructural modifications of MoSi2 through aluminum additions. Scripta Metall. Mater. 29, 1141 (1993).Google Scholar
15Silva, A. Costa e: Synthesis of Molybdenum Disilicide Composites Using In-Situ Reactions. 1994, University of Florida.Google Scholar
16Silva, A. Costa e: Applications of in situ reactions to MoSi2 based materials. Mater. Sci. Eng. A A195, 75 (1994).Google Scholar
17Schlichting, J.: Oxidation kinetic of silicon ceramic from the point of refractory materials resistant against hot corrosion. Rev. Int. Mautes Temp. Refract. 16, 67 (1979).Google Scholar
18Kodash, V.U., Kisly, P.S. and Shemet, V.J.: High temperature oxidation of molybdenum aluminosilicides. High Temperature Science 29, 143 (1990).Google Scholar
19Fitzer, E.: Heat Resistance and Corrosion of Sintered Materials. 2nd Plansee Seminar, Ruette/Tirol June 19–23, 1955.Google Scholar
20Westbrook, J.H. and Wood, D.L.: “Pest” degradation in beryllides, silicides, aluminides, and related compounds. J. Nucl. Mater. 12, 208 (1964).Google Scholar
21McKamey, C.G., Tortelli, P.F., De Van, J.H. and Carmichael, C.A.: A study of pest oxidation in polycrystalline MoSi2. J. Mater. Res. 7, 2747 (1992).CrossRefGoogle Scholar
22Berkowitz-Mattuck, J.B., Blackburn, P.E. and Felton, E.J.: The intermediate-temperature oxidation behavior of molybdenum dislicide. Trans. Metall. Soc. AIME 233, 1093 (1965).Google Scholar
23Berkowitz-Mattuck, J.B., Rosetti, M. and Lee, D.W.: Enhanced oxidation of molybdenum disilicide under tensile stress: Relation to pest mechanisms. Metall. Trans. 1, 479 (1970).CrossRefGoogle Scholar
24Berztiss, D.A., Pettit, F.S., and Meier, G.H.: Anomalous Oxidation of Intermetallics, in High-Temperature Ordered Intermetallic Alloys VI, Part 2, edited by Horton, J.A., Baker, I., Hanada, S., Noebe, R.D., and Schwartz, D.S. (Mater. Res. Soc. Symp. Proc. 364, Pittsburgh, PA,1995), p. 1285.Google Scholar
25Meier, G.H.: High temperature oxidaiton and corrosion of metal-silicides, in High Temperature Ordered Intermetallic Alloys II, edited by Stoloff, N.S., Koch, C.C., Liu, C.T., and Igumi, O. (Mater. Res. Soc. Symp. Proc. 81, Pittsburgh, PA,1987) p. 443.Google Scholar
26Meier, G.H. and Pettit, F.S.: High temperature oxidation and corrosion of intermetallic compounds. Mater. Sci. Technol. 8, 331 (1992).Google Scholar
27Meschter, P.J.: Low-temperature oxidation of molybdenum disilicide. Metall. Trans. A 23A, 1763 (1992).Google Scholar
28Kurokawa, K., Houzumi, H., Saeki, I. and Takahashi, H.: Low temperature oxidation of fully dense and porous MoSi2. Mater. Sci. Eng. A A261, 292 (1999).Google Scholar
29Kuchino, J., Kurokawa, K., Shibayama, T. and Takahashi, H.: Effect of microstructure on oxidation resistance of MoSi2 fabricated by spark plasma sintering. Vacuum 73, 623 (2004).CrossRefGoogle Scholar
30Viala, J.C., Fortier, P. and Bouix, J.: Stable and metastable phase equilibria in the chemical interaction between aluminum and silicon carbide. J. Mater. Sci. 25, 1842 (1990).Google Scholar
31Park, J.K. and Lucas, J.P.: Moisture effect on SiCp/6061 Al MMC: Dissolution of interfacial Al4C3. Scripta Mater. 37, 511 (1997).Google Scholar
32Iseki, T., Kameda, T. and Maruyama, T.: Interfacial reactions between SiC and aluminum during joining. J. Mater. Sci. 19, 1692 (1984).Google Scholar
33Iseki, T., Kameda, T. and Maruyama, T.: Some properties of Al4C3. J. Mater. Sci. Lett. 2, 675 (1983).CrossRefGoogle Scholar
34Choy, K.L.: Effects of surface modifications on the interfacial chemical stability and strength of continuous SiC fibers after exposure to molten aluminum. Scripta Metall. Mater. 32, 219 (1994).CrossRefGoogle Scholar
35Maruyama, B. and Rabenberg, L. Oxidation model of interface reactions in aluminum/graphite composites, in Interfaces in Metal Matrix Composites (Metallurgical Society of AIME, Warrendale, PA, 1986).Google Scholar
36Maruyama, B., Ohuchi, F.S. and Rabenberg, L.: Catalytic carbide formation at aluminum carbon interfaces. J. Mater. Sci. Lett. 9, 864 (1990).Google Scholar
37Sahoo, P. and Koczak, M.J.: Analysis of in-situ formation of titanium carbide in aluminum alloys. Mater. Sci. Eng. A144, 37 (1991).Google Scholar