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Loading Rate Effects on Ductile-Phase Toughening in In-Situ Niobium Silicide-Niobium Composites

Published online by Cambridge University Press:  26 February 2011

J.D. Rigney
Affiliation:
Case Western Reserve University, Cleveland OH,
JJ Lewandowski
Affiliation:
Case Western Reserve University, Cleveland OH,
L. Matson
Affiliation:
WRDC/MLLM, Wright-Patterson AFB, OH,
M.G. Mendiratta
Affiliation:
UES, Dayton, OH
D.M. Dimiduk
Affiliation:
WRDC/MLLM, Wright-Patterson AFB, OH,
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Abstract

Brittle silicide intermetallics such as Nb5Si3 have been significantly toughened by Nb particles incorporated during in-situ processing techniques. Ten-fold increases in toughness as well as resistance-curve behavior have been realized at conventional testing rates with these ductile Nb particles. Under more rapid loading rates the efficiency of the body-centered cubic (bcc) Nb particles in enhancing the toughness may be affected due to the strain-rate sensitivity of the Nb and/or the possible strain-rate sensitivity of interfacial debonding. Toughness tests conducted at loading rates of 0.0042 to 8.5 mm/sec have indicated a significant sensitivity to testing rate, with a drop in fracture toughness from 28 to 9 MPa√m over this range accompanied by a change in fracture mode from primarily ductile to cleavage failure in the Nb.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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References

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