Development of microstructural simulation tools for fusion materials

A key limitation in the advancement of nuclear fusion technologies is the development of materials for critical reactor components capable of withstanding enormous heat fluxes and stresses during service. To accelerate the materials development process, the UK Atomic Energy Authority (UKAEA) has undertaken a large-scale modelling research effort to predict the response of these materials under extreme conditions and have identified an urgent need for new material models at the microstructural scale.

During your PhD, you will develop these microstructural modelling capabilities for the fusion community with a multi-physics framework that is flexible, adaptable and user-friendly. The framework development will be driven by specific materials problems spanning the extremes of fusion materials: the effect of cyclic high heat flux on deformation in refractory W and the effect of evolving precipitation on the mechanical properties of Cu-Cr-Zr alloys. You will start by using full-field crystal plasticity and precipitation modelling to assess the dependence of plasticity on temperature and solute diffusion during the over-aging of Cu-Cr-Zr alloys while in service. Later, this will be combined with thermally activated dislocation-driven models for non-Schmid effects in BCC crystals to address the problem of cyclic heat loads and secondary stresses that develop in pure W during service.


Local stresses (right) and strains (mid) mapped onto the deformed configuration of the 30% cold-rolled and recrystallized representative volume element (left). Crystal plasticity simulations performed using DAMASK.

This work will be performed using the DAMASK simulation kit (damask.mpie.de), and you will have the opportunity to contribute to its development. You will work closely with other PhD students and senior researchers, using their data to help develop new models and obtain materials parameters. You will also have access to high-performance computing facilities at the University of Manchester and national facilities

The EPSRC Centre for Doctoral Training in Advanced Metallic Systems was established to address the metallurgical skills
gap, highlighted in several reports [1-3] as a threat to the competitiveness of UK industry, by training non-materials
graduates from chemistry, physics and engineering in a multidisciplinary environment. Although we will have supplied ~140
highly capable metallurgical scientists and engineers into industry and academia by the end of our existing programme,
there remains a demonstrable need for doctoral-level training to continue and evolve to meet future industry needs. We
therefore propose to train a further 14 UK based PhD and EngD students per cohort as well as 5 Irish students per
cohort through I-Form.

Manufacturing contributes over 10% of UK GVA with the metals sector contributing 12% of this (£10.7BN [4,5]) and
employing ~230,000 people directly and 750,000 indirectly. It is estimated that ~2300 graduates are required annually to
meet present and future growth [5]. A sizeable portion of these graduates will require metallurgical expertise and current
numbers fall far short. From UK-wide HESA data, we estimate there are ~330 home UG/PGT qualifiers in materials and
~35 home doctoral graduates in metallurgy annually, including existing AMSCDT graduates, so it is unsurprising that
industry continues to report difficulties in recruiting staff with the required specialist metallurgical knowledge and
professional competencies.

As well as addressing this shortfall, the CDT will also impact directly on the companies with which it collaborates, on the
wider high value manufacturing sector and on the UK economy as a whole, as follows:

1. Collaborating companies, across a wide range of businesses in the supply chain including SMEs and research
organisations will benefit directly from the CDT through:

- Targeted projects in direct support of their business and its future development and competitiveness.
- Access to the expertise and facilities of the host institutions.
- Involvement in the training of the next generation of potential employees with advanced technical and leadership skills
who can add value to their organisations.

2. The UK High-Value Manufacturing Community will benefit as the CDT will:

- Develop the underpinning science and advanced-level knowledge base required by future high technology areas, where
there is high expectation of gross added value.
- Provide an enhanced route to exploitation, by covering the full spectrum of technology readiness levels.
- Ensure dissemination of knowledge to the sector, through student-led SME consultancy projects, the National Student
Conference in Metallic Materials and industry events.

3. The wider UK economy will benefit as the CDT will:

- Promote materials science and engineering and encourage future generations to enter the field, through outreach
activities developed by the students that will increase public awareness of the discipline and its contribution to modern
life, and highlight its importance to future innovation and technologies.
- Develop and exploit new technologies and products which will help to maintain a competitive UK advanced
manufacturing sector, ensure an internationally competitive and balanced UK economy for future generations and
contribute to technical challenges in key societal issues such as energy and sustainability.

References:
1. Materials UK Structural Materials Report 2009
2. EPSRC Materials International Review 2008
3. EPSRC Materially Better Call 2013
4. The state of engineering, Engineering UK 2017
5. Vision 2030: The UK Metals Industry's New Strategic Approach, Metals Forum