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Electron Microscopy Studies Of Mo5Si3-MOSi2 Eutectic Composites Modified By Erbium Additions

Published online by Cambridge University Press:  15 February 2011

D. P. Mason ,
D. C. Van Aken  and
J. F. Mansfield
D. P. Mason
Affiliation:
Department of Materials Science and Engineering, The University of Michigan, 2300 Hayward St., Ann Arbor, MI 48109–2125
D. C. Van Aken
Affiliation:
Department of Materials Science and Engineering, The University of Michigan, 2300 Hayward St., Ann Arbor, MI 48109–2125
J. F. Mansfield
Affiliation:
Electron Microbeam Analysis Laboratory, The University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109–2143
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Abstract

Erbium additions to MO5Si3-MoSi2 eutectic composites have been investigated in an effort to reduce oxygen impurity levels found in the MoSi2 starting powders. Additions of 0.35 atomic percent Er were found to refine the script lamellar microstructure and increase the hardness of the composite as compared with the unmodified material. This increase in hardness was maintained over the temperature range 25°C to 1300°C. Oxygen rich Er particles have been observed in the Er-modified material suggesting that Er has acted as a gettering agent for oxygen. An intermetallic phase Er2Mo3Si4was also observed in the Er-treated material. The character of this phase was determined by convergent beam electron diffraction (CBED), wavelength dispersive spectroscopy (WDS) and X-ray dispersive spectroscopy (XEDS). The particles of Er2Mo3Si4 were found to be heavily faulted which caused a reduction in the experimental diffraction symmetries. Thus, ambiguities arose during CBED analysis. Therefore, a standard sample of Er2Mo3Si4 was prepared and used to aid in the identification of the faulted particles.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 273: Symposium Q – Intermetallic Matrix Composites II , 1992 , 289
Copyright
Copyright © Materials Research Society 1992

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References

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