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Phase Equilibria in the Nb-rich Nb-Ti-Si-Cr-Hf alloys

Published online by Cambridge University Press:  19 January 2011

Ying Yang
Affiliation:
CompuTherm LLC, Madison, Wisconsin 53719, USA
Bernard P. Bewlay
Affiliation:
General Electric Global Research, Schenectady, New York 12301, USA
Austin Chang
Affiliation:
University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Abstract

Refractory Metal-Intermetallic Composites (RMICs) based on the Nb-Si system have been considered as candidates for the next-generation high temperature materials (i.e. >1200°C). Ti, Cr and Hf have been shown to have beneficial effects on the oxidation resistance and mechanical properties of Nb-Si alloys. The present study has determined phase equilibria in the Nb-rich region of the Nb-Si-Ti-Cr-Hf system via the Calphad approach. The alloying effects of Cr and Hf on the microstructure of Nb-Si-Ti alloys are understood based on isothermal sections, liquidus projections, and solidification curves that were calculated from the thermodynamic models of the Nb-Ti-Si-Cr-Hf system developed in the present study. This work provides important guidelines on the development of new Nb-Si-Ti-Cr-Hf alloys.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

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References

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