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Anomalous Strengthening Mechanism in NbSi2-Based Silicide Single Crystals

Published online by Cambridge University Press:  21 March 2011

Yukichi Umakoshi ,
Takayoshi Nakano  and
Masafumi Azuma
Yukichi Umakoshi
Affiliation:
Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2–1, Yamada-oka, Suita, Osaka 565–0871, Japan
Takayoshi Nakano
Affiliation:
Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2–1, Yamada-oka, Suita, Osaka 565–0871, Japan
Masafumi Azuma
Affiliation:
Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2–1, Yamada-oka, Suita, Osaka 565–0871, Japan
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Abstract

Anomalous strengthening behavior of NbSi2-based silicide single crystals with C40 structure was examined focusing on the effect of substitutional alloying elements and the formation of a solute dragging atmosphere. After pre-straining to 1% at temperatures between 600 and 1600°C, single crystals were deformed at 400°C to examine the effects of dislocation sources and segregation of solute atoms around dislocations. The stress amplitude of yield drop was derived by the segregation of solute atoms at the superlattice intrinsic stacking fault (SISF) between two superpartials. Introduction of dislocation sources by pre-straining remarkably improved fracture strain, but the segregation of solute atoms around dislocations during pre-straining at higher temperatures induced a rapid drop of fracture strain. Change in the SISF energy by static and dynamic aging was observed to obtain evidence of segregation of solute atoms at the SISF between two superpartials.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 646 , 2000 , N2.5.1
Copyright
Copyright © Materials Research Society 2001

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References

REFERENCES

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