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Oxidation and Protection of Ti3AL-Based Intermetallic Alloys

Published online by Cambridge University Press:  01 January 1992

Douglas W. Mckee*
Affiliation:
General Electric Corporate Research and Development, P.O. Box 8, Schenectady, New York 12301.
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Abstract

Titanium aluminides containing 20-30 atom percent Al can suffer from severe subsurface embrittlement (alpha-case) when exposed to air at elevated temperatures for extended periods. For example.the alloys Ti-24Al-12.5Nb-l.5Mo and Ti-24Al-8Nb-2Mo-2Ta (based on the Ti3Al alpha-2 intermetallic compound) embrittle to a depth of about 80 microns during 1000 hours exposure to air at 815°C (1500°F), resulting in major reductions in tensile properties. Plasma-sprayed coatings of the MCrAlY and MCr types deposited over a thin diffusion barrier of chromium or tungsten, have been found effective in protecting these alloys against oxidation and embrittlement at this temperatures.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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