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Dislocation mechanisms in a zirconium alloy in the high-temperature regime: An in situ TEM investigation

Caillard, Daniel and Martin, Rautenberg and Feaugas, Xavier Dislocation mechanisms in a zirconium alloy in the high-temperature regime: An in situ TEM investigation. (2015) Acta Materialia, 87. 283-292. ISSN 1359-6454

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Official URL: https://doi.org/10.1016/j.actamat.2015.01.016

Abstract

Dislocation mechanisms responsible for the high-temperature mechanical properties of a Zr alloy have been investigated using in situ straining experiments between 250 °C and 450 °C. At 250 °C and 300 °C, the results show a steady and homogeneous dislocation motion in prismatic planes, with little cross-slip in the pyramidal and/or basal planes. At 350 °C, the kinetics of mobile dislocations becomes very jerky and inhomogeneous, in agreement with a dynamic strain aging mechanism. Above this temperature, the motion is again steady and homogeneous. Extensive cross-slip forms super-jogs which are efficient pinning points against the glide motion. These super-jogs move by glide along the Burgers vector direction, never by climb. The glide velocity between super-jogs is linear as a function of the total driving stress (applied stress minus line-tension stress due to dislocation curvature), in agreement with the solute dragging mechanism. The origin of the stress–strain rate dependence with an exponent larger than unity is then discussed.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Université de La Rochelle (FRANCE)
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Deposited By: Yves MOMBOISSE
Deposited On:02 Apr 2019 09:48

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