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Modeling of the Dislocation Dynamics in Ni3Al and the Flow Stress Anomaly

Published online by Cambridge University Press:  15 February 2011

B. Devincre ,
P. Veyssiere ,
L. Kubin  and
G. Saada Lem
B. Devincre
Affiliation:
CNRS-ONERA, 92322 Chatillon, France
P. Veyssiere
Affiliation:
CNRS-ONERA, 92322 Chatillon, France
L. Kubin
Affiliation:
CNRS-ONERA, 92322 Chatillon, France
G. Saada Lem
Affiliation:
CNRS-ONERA, 92322 Chatillon, France
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Abstract

Ni3Al single crystals are known to exhibit a flow stress anomaly between 200 and 800K. The purpose of our work is to examine such an anomaly by means of a simulation of the dislocation dynamics at a mesoscopic scale. The simulation basic rules are: i) the dislocation glide in {111} octahedral planes, ii) the conditions at which screw lines are locked and unlocked by the formation of Kear-Wilsdorf locks, iii) the mobility of jogs in the {100} cube plane. Our results suggest that two different temperature regimes occur in the domain of the anomaly. At low temperatures, the plastic flow is governed by kink bow-out, itself a function of the kink length. At high temperatures, the plastic flow is governed by the unlocking of the weakest Kear-Wilsdorf locks in the microstructure. These outcomes of the simulation are discussed in relation with the existing theoretical models of the flow stress anomaly.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 535
Copyright
Copyright © Materials Research Society 1997

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References

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