Research Studentship in Solid Mechanics and Materials Engineering: Irradiation Tolerance of Nanocrystalline Fe, Fe-Cr and Steels

Research Studentship in Solid Mechanics and Materials Engineering

Irradiation Tolerance of Nanocrystalline Fe, Fe-Cr and Steels

3.5-year D.Phil. studentship, fully funded for UK applicants, starting October 2022

Supervisors: Prof. Felix Hofmann (Oxford Engineering Science) & Dr. Pui-Wai (Leo) Ma (CCFE, UKAEA)

Research Summary

We are seeking a DPhil student to explore the irradiation-resistance of nano-structure, iron-based alloys for fusion power reactors. This EPSRC/UKAEA funded studentship is an exciting opportunity to benchmark new nanostructured materials for intense irradiation environments using state-of-the-art experimental techniques and large-scale computation methods. The central aim is to develop materials with exceptional radiation tolerance. These will be key to enabling commercially viable fusion power.

Material swelling due to irradiation is a major concern as it causes the build-up of internal stresses that reduce the fatigue life of components. Accumulation of irradiation defects is the main mechanism that drives swelling. Nanostructured/nanocrystalline materials promise to address this problem, as grain boundaries have been observed to act as efficient sinks for defects.

The goal of this project is to synthesise nano-crystalline Fe, Fe-Cr and steels, and to examine, by experiment and extensive computer modelling, how their microstructure, mechanical and thermal transport properties change under irradiation. Ferritic/martensitic steels are the most important structural materials for fusion reactors. Yet the radiation resistance of nano-crystalline iron-based alloys is almost completely unexplored.

You will learn to produce various nanocrystalline materials using high pressure torsion (HPT). These will then be irradiated with ions to mimic the effect of neutron irradiation in a reactor environment. You will learn to use electron microscopy and X-ray techniques to analyse the structural changes irradiation causes, and nano-indentation to quantify how mechanical properties evolve as a function of grain refinement and irradiation dose. You will also learn to use transient grating spectroscopy (TGS) to explore the evolution of thermal diffusivity and elastic properties in these samples. Together these characterisation techniques will give us a multi-facetted view of the irradiation damage performance of nanocrystalline iron alloys and their potential benefits.

You will combine these experiments with large-scale atomistic simulations to predict defect evolution and property change. To simulate irradiation to dose levels comparable with experiments, we will leverage high performance computing (HPC) resources at UKAEA and at national level. Simulations will be performed using tools developed at UKAEA, as well as freely available codes (LAMMPS, ATOMSK etc.). Using these simulations, we will endeavour to identify the underlying atomic-scale mechanism that govern behaviour.

The experimental part of this project will be supervised by Prof. F Hofmann. There will be strong synergies between this project and other activities in the Hofmann group focussed on irradiation damage, new microscopy technique development and severe plastic deformation. The computation part will be supervised by Dr. Pui-Wai (Leo) Ma of UKAEA, who has extensive experience in both electronic and atomistic scale simulations of metals and extracting information to continuum models.

You will be an integral part of the lively nuclear materials community in Oxford, with seminars and workshops, as well as the dynamic research community at CCFE. Weekly meetings of both provide an excellent platform for presentation of results and an active and stimulating environment for discussion. Further information about Prof. Hofmann’s research can be found at http://hofmanngroup.org, and additional information about CCFE/UKAEA work is available at http://ccfe.ukaea.uk/. Details about the University of Oxford Department of Engineering Science are available at https://eng.ox.ac.uk. 

Candidate Requirements

Prospective candidates will be judged according to how well they meet the following criteria:

·        Excellent degree in Engineering, Material Science, Physics, or another relevant discipline.

·        Strong mathematical and analytical skills.

·        Excellent written and spoken English communication skills.

·        Willingness to spend several weeks per year travelling to international collaborators and science facilities for experimental work (expenses will be covered).

The following skills are desirable:

·        Ability to program (e.g. in Matlab, Fortran or Python)

·        Enthusiasm for experimental work

·        Enthusiasm for modelling/simulation work.

Application Procedure

Informal enquiries are strongly encouraged and should be addressed to Prof. F Hofmann ([Email Address Removed] ) or Dr. PW Ma ([Email Address Removed] ).

Candidates must submit a graduate application form and are expected to meet the graduate admissions criteria. Details are available on the course page of the University website.

Please quote 22ENGCCFE_HM in all correspondence and in your graduate application.

Application deadline: 1 March 2022

Start date: October 2022