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Heat Treatments and Thermal Fatigue of Scs-6/Alpha-2 Titanium Aluminide Composites

Published online by Cambridge University Press:  21 February 2011

Y-W. Kim
Affiliation:
Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson Air Force Base, OH 45433-0511
J. Kleek
Affiliation:
Wright Research and Development Center, Materials Laboratory, WRDC/MLLS, Wright-Patterson Air Force Base, OH 45433-6533
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Abstract

Panel composites made of alpha-2 titanium aluminide (Ti-25A1-9Nb-1.6Ta-1.6Cr-lMo) foils and SCS-6 (SiC with carbon core and carbon double coatings) fibers were investigated to determine the influence of postprocessing heat treatments on the thermal fatigue behavior in air. The 4-ply composite panels with 22 vol% fiber showed no edge cracks after 1000 thermal cycles between 150°C and 816°C in alpha+beta or beta-solution plus isothermal-aging treatments. The thermal cycling, however, embrittled the fiber carbon core and coatings in the composites given post-processing heat treatments, with the degree of embrittlement increasing progressively with heat treatment temperature/exposure. The detrimental effects of heat treatments on the matrix were also observed in that beta treatments reduced both the strength and tensile ductility of the matrix alloy when compared with alpha+beta treatments.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

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