Deformation mechanisms of fusion energy materials: Revealing subsurface behaviour.

Harnessing nuclear fusion for the generation of energy requires large amounts of heat to be transferred from the plasma through the first wall of the reactor to the coolant, so it is crucial that heat transfer components are made from a highly conductive material. To ensure that the component performance and lifetime are suitable for use in a fusion reactor, other properties such as strength, irradiation resistance and fatigue behaviour must also be well understood.

The Cu-Cr-Zr system, a precipitation hardened alloy, is a leading candidate material for heat sink components. Developing suitable computational models to understand the alloy behaviour requires information about how individual crystals, and their positions in 3D, respond to the mechanical loads and thermal fluctuations that could be experienced during reactor operation.

This project will make use of 3D-X-ray diffraction (3DXRD) where the location, movement, orientation and stress state are tracked for several thousand crystals, in 3D, whilst being subjected to loading conditions. Results will be related to conventional surface-based characterisation methods as well as nanometre scale TEM studies to fully describe deformation structures and their relationship to microstructures.

As subsurface micromechanical behaviour of Cu-Cr-Zr and other candidate Cu-based alloys at the per-crystal level has been seldom explored, this project will provide comprehensive data that can be directly used to validate deformation models. By partnering with UKAEA, the relevance and implications of the new micromechanical understanding will be linked to real applications, both with and without irradiation.