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Solidification Processing Routes to High Aspect Ratio Reinforcements in γ-TiAl

Published online by Cambridge University Press:  21 February 2011

J. J. Valencia ,
J. P. A. Löfvander ,
J. Rösler ,
C. G. Levi  and
R. Mehrabian
J. J. Valencia
Affiliation:
Materials Department, University of California, Santa Barbara, CA 93106
J. P. A. Löfvander
Affiliation:
Materials Department, University of California, Santa Barbara, CA 93106
J. Rösler
Affiliation:
Materials Department, University of California, Santa Barbara, CA 93106
C. G. Levi
Affiliation:
Materials Department, University of California, Santa Barbara, CA 93106
R. Mehrabian
Affiliation:
Materials Department, University of California, Santa Barbara, CA 93106
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Abstract

Additions of ∼5%B1 and ∼9%Ta to binary γ-TiAl result in the formation of a monoboride isomorphous with TiB but containing Ta in solid solution. This boride exhibits strongly anisotropic growth from the melt, producing rod-like primary phases which are of potential interest for creep strengthening of the γ matrix. Fibrous borides with aspect ratios larger than ∼20 and volume fractions of ∼0.12 have been produced in arc-melted Ti-48AI-9Ta-4.3B alloys. Creep testing at 1255 K indicates that these “in-situ” composites have much higher creep strength than γ-TiAl, but the contribution of the reinforcements is relatively small compared with the solute-strengthening of the matrix.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 194: Symposium R – Intermetallic Matrix Composites I , 1990 , 89
Copyright
Copyright © Materials Research Society 1990

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References

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