Detail publikace
Uniqueness and stability of activated dislocation shapes in crystals
GRÖGER, R. ŠREMR, J. VYDROVÁ, J.
Anglický název
Uniqueness and stability of activated dislocation shapes in crystals
Typ
článek v časopise ve Web of Science, Jimp
Jazyk
en
Originální abstrakt
Simplified models of thermally activated dislocation glide constitute an important link between atomic-level studies of isolated dislocations and macroscopic thermodynamic properties of materials. These models rest upon the activation enthalpy, which is the energy to transform an initially straight dislocation into its activated state at finite applied stresses. Minimizing this activation enthalpy leads to a boundary value problem for the shape of the dislocation line. Besides two constant solutions corresponding to a straight dislocation in its stable and unstable states at the applied stress, there exist an infinite number of non-constant solutions. We investigate the characters of these solutions for dislocations anchored at their ends. Using the second variation of the activation enthalpy, we derive a set of conditions that define a unique activated state of the dislocation. The corresponding analysis demonstrates that the shape of the dislocation in this activated state must change with the applied stress to maintain the state of minimum activation enthalpy.
Anglický abstrakt
Simplified models of thermally activated dislocation glide constitute an important link between atomic-level studies of isolated dislocations and macroscopic thermodynamic properties of materials. These models rest upon the activation enthalpy, which is the energy to transform an initially straight dislocation into its activated state at finite applied stresses. Minimizing this activation enthalpy leads to a boundary value problem for the shape of the dislocation line. Besides two constant solutions corresponding to a straight dislocation in its stable and unstable states at the applied stress, there exist an infinite number of non-constant solutions. We investigate the characters of these solutions for dislocations anchored at their ends. Using the second variation of the activation enthalpy, we derive a set of conditions that define a unique activated state of the dislocation. The corresponding analysis demonstrates that the shape of the dislocation in this activated state must change with the applied stress to maintain the state of minimum activation enthalpy.
Klíčová slova anglicky
dislocations;slip;activation enthalpy;boundary value problem;uniqueness;stability
Vydáno
02.02.2021
Nakladatel
IOP Publishing Ltd
Místo
UK
ISSN
0965-0393
Ročník
2021
Číslo
29
Strany od–do
1–13
Počet stran
13
BIBTEX
@article{BUT169198,
author="Roman {Gröger} and Roman {Gröger} and Jiří {Šremr} and Jana {Vydrová},
title="Uniqueness and stability of activated dislocation shapes in crystals",
year="2021",
volume="2021",
number="29",
month="February",
pages="1--13",
publisher="IOP Publishing Ltd",
address="UK",
issn="0965-0393"
}