Supervisor: Dr Sam Humphry-Baker

The development of advanced shielding materials is critical to the deployment of fusion energy. Tungsten boride ceramics have recently been identified as prime candidate materials, but their high sintering temperature currently prevents metre-scale builds from being deployed. Their high brittleness also inhibits the shield from playing a structural role. This project will design and fabricate a new class of tungsten boride composites reinforced with a metallic phase to improve its fabricability and mechanical performance. Relationships between the sintering parameters, the composite microstructure, and the resulting properties will be systematically investigated. The student will use advanced microstructural characterisation tools such as electron-back scatter diffraction and dedicated high-temperature sintering and mechanical testing rigs withing the Centre for Advanced Structural Ceramics (CASC). They will work collaboratively with other group members to assess the irradiation damage performance of materials developed, and with fusion reactor constructors in the UK to understand how the composite microstructure affects its neutron shielding performance.

Supervisor: Dr Chris Gourlay

Project Description:

Al and Mg castings have great potential to simultaneously deliver lightweighting and cost savings in the aerospace and automotive sectors.  However, to be used more widely in these applications, damaging intermetallic compounds (IMCs) such as Al₁₃Fe₄ and Al₅FeSi must be understood and controlled during solidification to ensure the adequate ductility, fatigue performance and corrosion resistance of castings.  The research will focus on two areas: (i) the development of impurity-tolerant recycled Al- and Mg-alloys for automotive applications, and (ii) pushing the limits of high-purity Al- and Mg-alloy aerospace castings.  The project will build the understanding of the nucleation and growth of selected IMCs during solidification, and use this to control the IMC phases that form, their size, and their morphology.  The approach will combine solidification processing, a variety of characterisation techniques and thermodynamic modelling.

Supervisor: Prof David Dye, Prof Mary Ryan and Dr Finn Giuliani

Project description:

The next big challenge for UK decarbonisation is heating and cooling, which account for ~25% of global electricity demand and ~25% of UK CO₂ emissions from the use of natural gas in heating. Heat pumps, as used in refrigeration, are a feasible way to electrify and then decarbonise heating and cooling, and are already mandated in Holland as it looks towards the decommissioning of the domestic gas grid. Step-change improvements in heat pump efficiency are available from the substitution of the vapour compression cycle with cycles based on caloric materials. In this project we will pursue the development of CuZnAl elastocalorics for this application, focussing on improving their cyclic lives from ~10⁵ cycles presenting to the 10⁹ cycles required. We will also pursue options for coupling these with magnetocalorics to produce multi-caloric high surface area regenerator structures, e.g. through electrodeposition or through powder techniques such as metal injection moulding.  Finally, we will also examine the performance and degradation of such materials in demonstrator regenerators, with a particular focus on the interaction with the heat transfer medium (i.e. water). Techniques used will include 0.5kg-scale ingot melting and processing, , electron microscopy (incl (S)TEM, EBSD), with the potential to then use advanced characterisation techniques such as atom probe tomography and neutron and synchrotron x-ray diffraction.

Supervisors: Prof Fionn Dunne and Prof David Rugg (Rolls- Royce)

Project description:

Titanium alloys are used in safety-critical jet engine components and can sometimes undergo a degradation and failure process known as cold dwell fatigue. The mechanism is interesting since it is crucially sensitive to microstructure, particularly local crystallographic orientation, and to the creep deformation which takes place even at low homologous temperatures in these alloys.  We utilise crystal plasticity, discrete dislocation and molecular dynamics modelling techniques. In addition, quantitative characterisation and small-scale experimental testing with high resolution digital image correlation, high-res electron backscatter detection, and ultrasonic wave speed methods are also important. PhD projects in modelling and experimental studies (or preferably both) are available.

Supervisor: Dr Chris Gourlay

Project Description:

The solidification microstructure of microelectronic solder joints plays a key role in determining the reliability of electronics.  During soldering, it is common for solder balls to undercool below their liquidus temperature by tens or hundreds of Kelvin.  When nucleation occurs, rapid solidification is triggered and the undercooling at the growth front decreases due to latent heat release.  These phenomena lead to competition between different growth forms (dendrites, eutectic etc.) and complex microstructures form.  This project will study the undercooling-microstructure relationship in 100-500 micrometre diameter solder joints using differential scanning calorimetry (DSC) and electron microscopy.  The results will be used to develop microstructure selection maps that will improve the understanding of undercooling-microstructure-property relationships in Pb-free solder joints and guide new alloy development.

Supervisors: Prof Fionn Dunne and Mike Martin (Rolls-Royce)

Project description:

We wish to develop capabilities to address the problem of delayed hydride cracking in Zr cladding for the nuclear industry. Here, the role of hydrogen and its diffusion through the Zr alloy is crucial. Diffusion rates are strongly influenced by stress and the hydrogen concentration and temperature determine saturation when hydrides potentially form. These phases may, under thermal cycling, crack and lead to subsequent fatigue crack propagation. The new project is to establish crystal plasticity coupled hydrogen diffusion models, including hydride formation and dissolution, with crack nucleation and growth such that computational predictive modelling can be developed for Zr component design for reactor cores.  The project is largely theory/computationally based but there is scope for interested applicants for focused small-scale experiments with our existing kit for thermomechanical loading with specialist characterisation involving high resolution digital image correlation and high-res electron backscatter detection.

Funding Details (Home students only).:

50% funded by Rolls-Royce, incl top-up of bursary to £20k for 4 years.

50% funded by Nuclear CDT, Department or Faculty of Engineering DTA CASE conversion

Project supervisor: Dr Minh-Son Pham

Project description:

We recently presented a groundbreaking research that leads to a new generation of meta-materials mimicking crystal microstructure found in high performance metallic alloys (refer to M.S. Pham et al., Damage-tolerant architected materials inspired by crystal microstructure, Nature 2019; 565:305). The design of these new meta-materials is realised by additive manufacturing via 3D printing, offering an innovative way to fuse the metals science and 3D printing to design advanced materials with desired properties. This Phd studentship will explore many more exciting opportunities offered by this approach, in particular when combining this approach with multi-functional materials to develop high strength programmable materials. The qualified candidate will use various computer software to mimic microstructure found in nature to design new meta-materials that are not only mechanical robust, but also adaptive. S/he will use advanced 3D printing and material characterisation techniques to fabricate and study the behaviour of designed materials. S/he needs to team up with other students and effectively collaborate with our key academic and industrial partners in UK, France and USA.

Supervisor: Prof David Dye and Dr Mark Hardy (Rolls-Royce)

Project Description:

We have been developing new polycrystalline Co/Ni-base superalloys for jet engines for a number of years and hold several patents. They have now reached a stage of maturity where applications are coming into view, with tensile, creep and oxidation behaviour that exceeds those of alloys in service in many instances. From ingot and powder route starting points, the next steps are to develop these for additive layer manufacturing, ring rolling and extruded parts.  Technique opportunities include the EBSD examination of deformation substructures, (S)TEM, synchrotron x-ray and neutron diffraction, mechanical characterisation (i.e. forging, fatigue) and atom probe tomography (with Oxford or MPIE Dusseldorf).

Funding Details

50% funded by Rolls-Royce, incl top-up of bursary to £20k for 4 years.

50% funded by Characterisation CDT, Department or Faculty of Engineering DTA CASE conversion (Home students only).

Supervisor: Prof Baptiste Gault and Prof Eduardo Saiz

Project description:

Bone can self-regenerate, however, often bone regeneration is enhanced by the use of a “bone graft”. Synthetic bone grafts from calcium phosphates (CaPs) have raised interest due to their similarity to the mineral composition of bone, their abundance, and their excellent clinical performance. Most efforts to use CaP as bone substitutes have been devoted to sintered CaP such as hydroxyapatite, β-tricalcium phosphate and their composites called biphasic CaPs (BCP). Numerous studies have investigated the in vivo behavior of CaP and have revealed that HA, β-TCP and BCP are resorbed by cell-mediated acid-driven dissolution, with preferential attacks at grain boundaries that threaten the structural integrity of the ceramics. Not all grains and grain boundaries are susceptible to these attacks, or at least not at the same rate, which could be related to the specific composition of the grain boundaries. Doping was shown to lead to changes in the dissolution behaviour, but the reasons underpinning this change are still unknown. To address this significant knowledge gap, we propose a project focused on the measurement of the composition of grain boundaries at the atomic scale using atom probe tomography, combined with electron microscopy where necessary, on a series of model ceramics with controlled levels of dopants. By relating the composition of grain boundaries to their in vitro and in vivo behaviour, we hope to pave the way for designing biologically more potent ceramics, in particular ceramics with osteoinductive properties. 

This project will be under the supervision of Dr Baptiste Gault and Prof. Saiz at Imperial College London and in collaboration with Dr. Marc Bohner from the RMS Foundation (https://www.rms-foundation.ch/en/staff-member/marc-bohner.html)  for the synthesis and in vitro tests. Most of the work is to be conducted at the Max-Planck-Institute für Eisenforschung in Düsseldorf, Germany, where Dr Gault is based. 

Supervisors: Shelly Conroy, Peter Petrov, Neil Alford

Dynamic structures with non-trivial topology — such as skyrmions, merons, and domain walls — are rich sources for emergent functional phenomena, enabling local control of magnetic, electronic and ionic transport properties, phonons and more. Higher-order topological charge and spin textures in quantum materials provide a route to develop a plethora of  dynamic nanoelectronics, spintronics and quantum devices. Due to the complex local atomic scale structure of such topologies and related crystallographic defects, it is essential for the physical characterisation to be time-resolved and at this scale spatially.

Building on the recent progress in our groups, this PhD project will develop thin film growth methods of oxide quantum materials at the new state-of-the-art Imperial Royce facilities. The student will apply the latest tools in in-situ electron microscopy, diffraction and spectroscopic characterisation. Using sub-ångström electron beam probes the student will be able to draw and move exotic topologies in the materials they have grown, while analysing changes in their functional properties such as electric and magnetic field. In collaboration with the Imperial-X centre the student will incorporate machine learning approaches to probe the atomic-scale dynamics of the materials

The position is suitable for those with a background in chemistry, physics, nano-electronics, or materials science with an interest in quantum materials, atomic scale microscopy and scientific computing. The student will also utilise the new Cryogenic Transmission Electron Microscopy and the UK National Research Facility for Advanced Electron Microscopy SuperSTEM.  The student will spend a research internship at the Molecular Foundry, Lawrence Berkeley National Laboratory working in Dr Colin Ophus’ and Dr Sinéad Griffin’s groups.

Publications linked to the project:

1. Charged domain wall and polar vortex topologies in a room-temperature magnetoelectric multiferroic thin film. ACS Applied Materials & Interfaces (2022); doi: 10.1021/acsami.1c17383
2. Metal–ferroelectric supercrystals with periodically curved metallic layers. Nature Materials (2021) doi:10.1038/s41563-020-00864-6

2. TopoTEM: A Python Package for Quantifying and Visualizing Scanning Transmission Electron Microscopy Data of Polar Topologies. Microscopy &Microanalysis (2022); doi: 10.1017/S1431927622000435

3. Probing the Dynamics of Topologically Protected Charged Ferroelectric Domain Walls with the Electron Beam at the Atomic Scale. Microscopy & Microanalysis (2020); doi:10.1017/S1431927620023594

Supervisor: Prof Norbert Klein

Project Description:

This PhD project is aiming to develop microfluidic methods for label free detection of tumour cells based on physiological cell properties like cell size, hydration level and electronic properties (see research website  https://www.imperial.ac.uk/people/n.klein/research.html).  Microwave radiation penetrates through the cell membrane, allowing an unshielded view into the cell interior. The project will be continuation of a previous PhD project on this topic, and will include cell manipulation by dielectrophoresis. The student will work as member of an interdisciplinary team of physicists, engineers and life scientists and will receive training in microfabrication and microfluidic technology, microwave and electromagnetic measurement techniques, and biomedical device assessment in a clinical environment.  We are aiming to develop of novel tool for liquid biopsies, which will potentially reduce the use of tissue biopsies for monitoring tumour progression and improve the accuracy of early stage cancer detection. Candidates should have a passion for this topic and a master’s degree in Physics,  Materials Science, Electrical- or Bioengineering or related disciplines. The student will use our clean room facilities for the preparation of microfluidic channels and our unique microwave and cell characterization laboratory with state-of-art microwave network analysers, microfluidic equipment and fluorescence microscopy for device characterization and clinical applications.

Supervisor: Prof Norbert Klein

Project Description:

Detection of several disease markers simultaneously in real time using simple, low-cost and miniaturized devices on one chip is a first step toward personal disease diagnosis. This PhD project is aiming to develop a platform for electrical detection of several disease markers using graphene-field-effect-transistor sensors arrays. This project will be a continuation of our recent work on the detection of exosomes using graphene-field-effect-transistor sensors (see research website  https://www.imperial.ac.uk/people/n.klein/research.html). The student will work as member of an interdisciplinary team of physicists, engineers and life scientists and will receive professional training in clean room techniques and graphene preparation, electrical device characterization and microfluidic technology. She/he will use our cleanroom facilities to fabricate arrays of graphene-field-effect transistors using microfabrication techniques, functionalize the transistors using specific linker molecules, design 3D moulds for incorporating different antibodies onto specific graphene sensors, and integrate the transistor array with microfluidic channels and carry out the electrical measurements. This project is particularly important for the detection of early stages of cancer and could be a powerful tool towards personal medicine. Candidates should have a passion for this topic and a master’s degree in Physics, Materials Science, Electrical- or Bioengineering or related disciplines.

Supervisors: Dr. Ayman El-Zoka, Prof. Baptiste Gault

Early experimental work revealed the formation of uniformly nanoporous structures by dealloying AgAu for making nanoporous gold (NPG) that exhibits exciting functional properties. Dealloying is a complex process and ex-situ studies cannot fully resolve some intricate atomic-scale details at the dealloying interface and at the surfaces of the nanoligaments formed as a result. In this project, we will be pioneering the use of the burgeoning technique of cryo-atom probe tomography to probe the morphology and chemistry of the liquid-solid interface in real time and space, nearly atom by atom. Systematic analyses at different electrochemical conditions will help us refine existing models on nanoporous metal formation by corrosion, and to define pathways for their optimization for catalytic activity.

Supervisor: Dr Reshma R Rao

Co-Supervisor: Prof Mary Ryan

Hydrogen will play a critical role in the transition to a zero-carbon economy due to its widespread applications as a fuel for transport, feedstock to chemical industries and a source of heat. The hydrogen demand in the UK alone is forecast to increase to ~700 TWh (~10 million tonnes) by 2050, however, production today is a small fraction of this (~27 TWh), with only ~4% produced renewably (HM Govt. 2021 UK Hydrogen Strategy (ISBN 978-1-5286-2670-5)). Using renewable energy to convert low-grade water such as seawater and wastewater to high-value fuels such as hydrogen enables a secure energy future. The direct use of low-grade water to produce green hydrogen eliminates the use of water purification technologies required for current electrolysers, and thus widens the global reach of green hydrogen technologies (Tong, W., et al. (2020). Electrolysis of low-grade and saline surface water. Nature Energy, 5(5), 367-377. https://doi.org/10.1038/s41560-020-0550-8). However, the long-standing challenge of using low-grade water is the deleterious effect of ions and contaminants in it on the stability, activity and selectivity of catalysts. The poor performance of catalysts in these environments has a direct impact on the device efficiency and lifetime.

In order to design more flexible and resilient water electrolysis systems, we need to develop a fundamental understanding of how catalyst materials perform in harsh operating environments and use this information to rationally design new catalysts. The aim of this project is to elucidate the key factors controlling stability and activity of catalysts for low-grade water electrolysis. The project will involve (a) catalyst synthesis and characterization (b) benchmarking of electrochemical performance (c) operando optical and X-ray spectroscopy to understand how the catalyst structure and surface intermediates evolve with potential and time of operation and (d) post-mortem characterization using a suite of surface characterization tools available at the Department of Materials to detect changes in the surface properties. In essence, this project will enable accelerated materials discovery by understanding and controlling atomic-level properties of the catalyst. The student will work in a very collaborative environment and will have the opportunity to interact with several research groups across Imperial College and the UK, as well as with industrial project partners through this project.

Supervisor: Prof Peter Haynes

Project description:

The simulation of quantum materials and molecules have been identified as promising early applications of quantum computers due to the equivalence of entanglement and the correlation of the motion of electrons [1]. The so-called era of Noisy Intermediate-Scale Quantum (NISQ) technology [2] is just around the corner and promises universal quantum computing with 50–100 qubits that are capable of performing tasks beyond classical computers but limited by noise in the number of quantum gates that can be connected into a circuit to execute a given quantum algorithm. Simulations of small molecules and simple models of materials have already been demonstrated on six-qubit hardware [3] and 20-qubit machines are now available. This project will be associated with a collaboration with Professors Myungshik Kim and Johannes Knolle in Physics and funded by Samsung. We will apply emerging algorithms for quantum computers such as variational quantum eigensolvers to more realistic models of polymers and molecules parametrised by first-principles simulations on classical computers.

1. Richard Feynman, Int. J. Theor. Physics 21, 467–488 (1982)
2. John Preskill, https://arxiv.org/abs/1801.00862
3. Abhinav Kandala et al., Nature 459, 242–246 (2017)

Supervisor: Prof Robin Grimes

Project Description:

It is straight forward to model the melting of single component metals and simple binary compounds such as oxides. Molecular dynamics is good at following the solid/liquid interface as it moves into the solid.  But when the solid has two or more components, phase diagrams tell us that at equilibrium the solid and liquid have different compositions.  The liquid is dissolving a solid of a different composition.  What happens at the interface?  How do the atomic scale kinetic processes of diffusion at the interface control dissolution into the viscous liquid?  Despite being poorly understood, this atomic scale phenomenon controls general processes from solidification in metals processing to liquid phase sintering in ceramics but also specific issues such as the progression of accidents in a nuclear reactor core.  In this project we will use molecular dynamics to consider binary metallic systems for joining applications and refractory oxides in the nuclear industry.  We will collaborate with colleagues in the metals processing group at Imperial and the nuclear group at the University if New South Wales in Australia.

Supervisor: Dr Johannes Lischner

Project Description:

Twisted bilayer materials are fabricated by stacking two two-dimensional (2D) materials on top of each other and rotating one with respect to the other creating a beautiful moiré pattern. The interaction of the electrons with this moiré pattern results in novel emergent properties such as metal-insulator transitions or superconductivity. In this project, we will develop new theoretical tools to predict the properties of twisted bilayer materials and use them identify pairs of 2D materials with novel functionalities. We work closely with experimental groups to test the predictions of our calculations.