The plastic deformation of materials is generally governed by the generation and motion of dislocations through the crystal lattice. Microstructural features such as grain boundaries, precipitates and inclusions impede the dislocation motion causing strengthening but often limiting ductility. Dislocations often accumulate in the vicinity of these microstructural features and their mutual interactions and reactions lead to further increased hardening and local hot spots in stress that can lead to failure initiation. Understanding the behaviour of the dislocation ensemble is complex due to the many body interactions that take place.
This project will continue development of discrete dislocation plasticity simulations with the particular aim of extending present capabilities from simple single phase, single crystal models to more complex geometries incorporating the grain boundaries and precipitates that are more representative of real engineering alloys. Coupled diffusion models allowing development of the microstructure concurrent with plastic deformation will also be considered.
These models and simulations are of particular interest in fusion energy because not only do they offer mechanistic insight into the damage sustained by tokamak reactor walls, but can prove useful in designing better-suited materials for all aspects of fusion energy production.