Advanced Microstructure Characterisation of Fusion Structural Materials subject to Simultaneous Creep and Irradiation

Project Description:

Engineering assurance for the UK Spherical Tokamak for Energy Production (STEP) presents a materials challenge, but also opens many opportunities to better exploit recent progress in advanced characterisation and modelling tools. A top-down design approach is currently considered for the materials qualification and structural integrity assessment for two key structural materials, namely, CuCrZr alloy and reduced-activation ferritic/martensitic (RAFM) steel. This approach takes the crystal plasticity finite element modelling (CPFEM) as the core simulation tool and aims to overcome the trade-off between accuracy and efficiency, realising its real-world applications. Creep is a high-temperature deformation mode which is highly influenced by irradiation during loading.

The aim of this PhD work is to characterise both deformation and fracture mechanisms in relation to the microstructural evolution of CuCrZr alloy and RAFM steel subject to simultaneous creep and proton irradiation. You will perform 3D correlative microscopy studies by using the UK’s first-of-its-kind characterisation facility (the Hercules package) to create microstructure-related material database. The rich information across length-scales will be utilised for calibration of the CPFEM models that rely on the capture of the most important microstructure features. You will also employ deep learning-based convolutional neural networks to automate classification and quantification of key microstructure features as well as detection and clustering of damage sites from images. This project also comes with financial supports for attending international meetings/workshops.

Project snapshot overview

The PhD project is formulated in a step-by-step manner by first examining the CuCrZr alloy with a simpler microstructure, followed by probing into the hierarchical microstructure of the RAFM steel. CuCrZr is a polycrystalline and precipitation hardened alloy with fcc-Cu as matrix and Cr-rich precipitates. Its unirradidated microstructure is characterised by a grain size of 30 mm and a high volume fraction of nanometre-sized precipitates. Characterisation of the microstructural and property changes that occur as a response to proton irradiation of CuCrZr alloy forms an important part of this PhD. By contrast, RAFM steel has a very complex and hierarchical microstructures consisting of ferrite and tempered martensite and prior-austenite grain boundaries, together with M23C6 and MX precipitates decorating the laths as well as tantalum oxide inclusion. This complexity makes it challenging to establish reliable and mechanism-based microstructure-property relationships. This forms the second important part of this PhD. To solve this challenge, you will be undertaking collaborative research with many academics outside Leicester (e.g., Oxford and Manchester via networking opportunities and NNUF funded user access scheme).

Entry requirements

Applicants are required to hold/or expect to obtain at least a UK Bachelor Degree 2:1 or better, or overseas equivalent in materials science, mechanical engineering or relevant subject area.

The University of Leicester English language requirements apply

In addition, successful applicants should meet the following

Familiar with mechanics of materials (or physical metallurgy of steels or relevant metallic materials) preferably with some experience of analytical and numerical materials modelling

Demonstrable experience of analytical and/or numerical materials modelling, via Matlab, computer programming/coding, and/or numerical simulation software (e.g. ABAQUS)

Good written and oral communication skills and teamwork attitude

Informal enquiries

Project / Funding Enquiries: yl832@leicester.ac.uk

Application enquiries to engineeringpgr@le.ac.uk

See our web page for full details of how to apply.

https://le.ac.uk/study/research-degrees/funded-opportunities/eng-chen-advanced-microstructure

Application form