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Deformation Microstructures in B2-Type CoTi Single Crystals

Published online by Cambridge University Press:  26 February 2011

M. Yoshida  and
T. Takasugi
M. Yoshida
Affiliation:
Miyagi National College of Technology, Natori, Miyagi-pref., 981–12, Japan
T. Takasugi
Affiliation:
Institute for Materials Research, Tohoku University, Katahira 2–1–1, Sendai 980, Japan
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Abstract

B2-type CoTi single crystals which exhibit the yield strength anomaly were deformed at various temperatures and on various compression axis in order to investigate the deformation microstructures. The morphological feature and Burgers vectors of the activated dislocations were investigated by means of transmission electron microscopy. At a low temperature of 300 K, relatively straight dislocations with the <001>-type Burgers vector were observed. They consisted of the mixed components of edge and screw, and strongly tended to form the dipoles. At a temperature of 773 K where the yield stress increases with increasing temperature, the screw components of dislocations with a <001>-type Burgers vector were dominant and showed peculiar morphology revealing the pinning or cross slip. However, the examination using the weak-beam method could not show the evidence of any dissociation. At a high temperature of 973 K above the peak temperature, the Burgers vectors of activated dislocations were determined to be a <001>- type for compressive orientation axes close to [111] and [011] whereas a <110>-type for orientation axis close to [001]. These dislocation microstructures were discussed in correlation with the yield strength anomaly observed in these intermetallics.

Information

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 213: Symposium Q – High-Temperature Ordered Intermetallic Alloys IV , 1990 , 273
Copyright
Copyright © Materials Research Society 1991

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References

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