Mesoscopic plasticity and the vortex density model of superconductivity
Lead Research Organisation:
University of Oxford
Department Name: Mathematical Institute
Abstract
Local mismatches in the atomic structure of a crystalline material are known as dislocations, and may be modelled as line sources of stress. Dislocations move around in a material in response to stress(each confined to a particular plane known as the slip plane), and may become tangled. Under cyclic loading of a material such as copper it is observed that a ``microstructure'' forms in which dislocations separate into regions of high dislocation density and regions of near pristine material. Mathematically similar line singularities occur in the theory of superconductivity, where they are known as flux tubes, or superconducting vortices. These vortices move in response to an electric current in the same way that dislocations move in response to stress.Superconducting vortices exhibit an instability in which a single straight line vortex may develop a helical structure. The goal of this project is to analyse the analogous problem in dislocation dynamics, to determine whether the corresponding instability has a role to play in the formation of the dislocation microscructure.
Organisations
People |
ORCID iD |
S Chapman (Principal Investigator) |
Publications
Acharya A
(2012)
Elementary observations on the averaging of dislocation mechanics: Dislocation origin of aspects of anisotropic yield and plastic spin
in Procedia IUTAM
Zhu Y
(2013)
Dislocation motion and instability
in Journal of the Mechanics and Physics of Solids
Description | This award aimed to transfer technology developed to understand instabilities of vortices in fluids and superconductors to examine whether similar instabilities could exist for dislocations in an elastic crystal. In this it was successful: a new instability of dislocations was identified and characterised. This instability has implications for the generation of new dislocations, and therefore, ultimately, for the plasticity of metals. |
Exploitation Route | The visiting researcher has already been taking these findings forward to incorporate into mesoscale models of plasticity. |
Sectors | Aerospace, Defence and Marine,Manufacturing, including Industrial Biotechology |