Events in Physics
Steven Fitzgerald, Culham
Unstable Dislocations in Anisotropic Crystals
Dislocations are line-like objects with an associated elastic energy proportional to their length. Therefore, it would seem sensible to consider a positive line tension encoding their resistance to elongation. If we confine the dislocation to a plane, this tension is given by E + E", where E is the energy per unit length and the derivatives are taken with respect to the angle in the plane. When the crystal is isotropic, this quantity is always positive, and dislocations will assume a smooth elliptical shape at equilibrium. In highly anisotropic crystals, however, E + E" can become negative for certain orientations. This counter-intuitive notion (a dislocation can reduce its energy by increasing its length) leads to unusual cusped dislocation configurations, which have been observed in the electron microscope. It may also provide a possible explanation for the observed plastic weakness of iron and ferritic steels in the highly anisotropic (high temperature) regime.
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Due to the implementation of a new UKRI funding system (TFS) there will be a fixed quarterly deadlines for some grants which would previously have been on open calls, this is to allow necessary system amendments and updates.
The first deadline after implementation will be 28th September 2023 and applies to those calls listed below:
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