By John P. Hirth
New versions for dislocation constitution and movement are provided for nanocrystals, nucleation at grain barriers, stunned crystals, interphase interfaces, quasicrystals, advanced buildings with non-planar dislocation cores, and colloidal crystals. A assessment of experimentally demonstrated major good points of the magnetoplastic impact with their actual interpretation explains many diversified result of this kind. The version has many strength functions for forming procedures motivated by way of magnetic fields.
• Dislocation version for the magnetoplastic effect
• New mechanism for dislocation nucleation and movement in nanocrystals
• New types for the dislocation constitution of interfaces among crystals with differing crystallographic structure
• A unified view of dislocations in quasicrystals, with a brand new version for dislocation motion
• A normal version of dislocation habit in crystals with non-planar dislocation cores
• Dislocation houses at excessive velocities
• Dislocations in colloidal crystals
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Additional resources for Dislocations in Solids, Vol. 14
For example the splitting distance between the leading and trailing partial is a strong function of the local stress within the grain and therefore variations in stress within a grain will lead to variations in the splitting distance along the dislocation line . The type of GB influences how easily a dislocation propagates by depositing itself into the GB. For example the GB on the right in Figs 11 and 12 is under a tension, and deposition of the full dislocation into the GB occurs without any difficulty.
What has to be drawn as a conclusion from these results is that the competition between the nucleation of a leading dislocation, the nucleation barrier for a trailing dislocation, the additional amount of structural relaxation in the GBs accompanying nucleation and absorption processes is heavily influenced by the applied stress level in the simulation and therefore MD simulations alone cannot alone be used for extracting rate limiting nucleation criteria as a function of stress or grain size. This picture becomes even more complicated when one realizes that the amount of structural relaxation and atomic activity observed during nucleation/propagation and absorption of dislocations in an MD simulation might be unrealistically high, due to the lack of a realistic impurity content within the GB.
Figure is taken from Ref. . 30 H. M. Derlet Ch. 81 Fig. 16. Cross-section of a twinned grain. The (111) planes, indicated by white, show the original position of the neighbor twin-boundary samples. Figure is taken from Ref. . Fig. 17. Dislocations moving in regions constrained by twin boundaries in the nc Cu sample containing twin on low Schmid factor 111 planes. Figure is taken from Ref. . planes where chosen to be on high Schmid factor planes, extended partial dislocations on planes parallel to the twin planes were observed.