Understanding how irradiation damage from neutrons affects the mechanical properties of structural materials is a key step towards realising nuclear fusion as a sustainable power source. However working on irradiated materials is costly, and generating mechanical data from them is difficult. Neutron damage can be simulated with ion irradiations but the damage layers are thin - 200nm to 100µm. As such traditional mechanical testing methods cannot be used and novel micro-mechanical tests must be conducted. This leads to difficulties in interpreting the results due to size effects inherent in testing small material volumes.
This project will involve coding, debugging and performing simulations with state of the art computer models being developed in Oxford namely a coupled 3D (DDP) discrete dislocation plasticity / finite element code and a crystal plasticity finite element code (Abaqus UMAT) to simulate nano-indentation experiments. The experiments you will simulate are being performed at the Materials Research Facility at the Culham Centre for Fusion Energy to study the effects of ion irradiation on fusion materials and correlate this with the defect populations produced. The insight gained will then be used to develop methods to use small scale mechanical tests to aid engineering design of future fusion systems. Materials of interest include chromium, vanadium and tungsten based alloys.
Key challenges will be how to accelerate the code using a GPU, how to implement the correct traction/displacement boundary conditions, and how to incorporate complex geometry such as multiple precipitates. You will be part of a small team developing the codes and performing simulations and will also interact closely with experimental researchers at MRF at CCFE as well as work in the Oxford Materials Department and therefore will have access to rich data sets to validate and improve the model. The ultimate goal of the project is to be able to perform virtual experiments that reproduce real experiments and in doing so fully understand the mechanisms which control deformation of irradiated materials.