Stability and Motion of Low Angle Dislocation Boundaries in Precipitation Hardened Crystals

David Holec; Antonín Dlouhý

doi:10.4028/www.scientific.net/MSF.482.159

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HomeMaterials Science ForumMaterials Science Forum Vol. 482Stability and Motion of Low Angle Dislocation...

Stability and Motion of Low Angle Dislocation Boundaries in Precipitation Hardened Crystals

Abstract:

The present study investigates stability and motion of low angle dislocation boundaries in an array of precipitates. The model considers discrete dislocations and precipitates that are treated as impenetrable particles. Peach-Koehler forces, which originate due to the combined effect of dislocation-dislocation interactions and the applied stress, act the individual dislocations on. Both, the dislocation glide and the dislocation climb at elevated temperatures are taken into account. Results of the numerical study suggest that a critical applied shear stress (CASS) always exists which separates stable and unstable low angle boundary configurations. Varying particle size, interparticle spacing and density of dislocations in the boundary cause changes of the CASS that are systematically investigated. It is shown that the CASSs can considerably differ from the standard Orowan stress controlling the equilibrium of an isolated dislocation in a given microstructure. This result underlines the importance of long-range dislocation interactions that influence the high temperature strength of the precipitation-hardened alloys.

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Periodical:

Materials Science Forum (Volume 482)

Pages:

159-162

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.482.159

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Online since:

April 2005

Authors:

David Holec, Antonín Dlouhý

Keywords:

Dislocation Motion, Low Angle Dislocation Boundary, Orowan Stress, Precipitation Hardening

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