Dynamic Aging of Dislocations in Materials with a High Crystalline Relief: Competition of Diffusion and Dragging Impurities

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Dynamic Aging of Dislocations in Materials with a High Crystalline Relief: Competition of Diffusion and Dragging Impurities

September 9, 2021 Chemical Science 0

In crystals with a high lattice potential relief (Peierls barriers), a model of the dynamic interaction of dislocations with the impurity subsystem has been created. Metals with a body-centered cubic structure, semiconductors, and a variety of other materials fall into this category. The inverse influence of impurities entrained by moving dislocations on the dynamics of the dislocations themselves is taken into consideration in the built theory of the dynamic interaction of dislocations with the impurity subsystem of the crystal. The presence of two stages in the impurity kinetics during atmosphere creation is justified. The first (initial) step is quick and essentially non-equilibrium, followed by a slower approach to equilibrium in the second stage. The first stage presents itself at a sufficiently fast dislocation motion and may result in an abnormal increase in the driving force (or the material’s yield strength) as the temperature rises in a certain range. The self-consistent character of the mechanism causes instability in dislocation movement in a specific speed range and dislocation immobilisation at loads below a certain threshold. Impurities that obstruct dislocation motion may create an inverse brittle–ductile transition, which has been reported in some materials with an increase in temperature (rather than the typical drop).

Author (S) Details

B. V. Petukhov
Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333, Moscow, Russia.

View Book :- https://stm.bookpi.org/CACS-V4/article/view/3051

 

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