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The Yield Stress Anomaly in Ll2 Alloys

Published online by Cambridge University Press:  01 January 1992

Peter B. Hirsch
Peter B. Hirsch*
Affiliation:
University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH, England.
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Abstract

The implications of the basic assumptions of the local pinning theories for the yield stress anomaly in Ll2 alloys are discussed. An alternative theory is presented in which the superpartials on (111) cross-slip on to (010) to form long locks lying partially on (111) and (010) or completely on (010) planes (Kear-Wilsdorf locks). The ends of the locks are joined by glissile superkinks. The yield stress is controlled by superkinks bypassing the screw dislocation locks, and the increase of the yield stress with increasing temperature is due to the decrease of the lengths of superkinks. The theory accounts satisfactorily for the mechanical properties including the small strain-rate dependence of the yield stress and is consistent with electron microscope observations.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 288: Symposium L – High-Temperature Ordered Intermetallic Alloys V , 1992 , 33
Copyright
Copyright © Materials Research Society 1995

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References

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