Fully funded Departmental PhD projects (including DTP)

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: Huan (Ann) Chun

Next generation of batteries such as solid-state batteries (SSBs) has great potential to improve the safety and energy storage performance of current lithium ion batteries (LIBs). However, slow ion diffusion in SSBs has currently restricted their performance. The research will focus on two areas for electric automotive applications: (i) the development of new electrode and solid-state electrolyte materials for SSBs, and (ii) fabricating the electrodes into batteries using state-of-the-art processing, characterisation and performance testing facilities. The project will build the understanding of chemistry and materials science to produce SSBs with performance superseding current LIBs. The approach will combine processing techniques, a variety of characterisation techniques and modelling.

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 Nima Haghdadi

Metal additive manufacturing (AM), also known as 3D printing, is a disruptive manufacturing technology in which complex engineering parts are produced in a layer-by-layer manner, using a high-energy heating source and powder, wire, or sheet as feed material. AM provides unique opportunities for creating metallic parts with reduced material waste, development costs, and production lead times. However, there are challenges in producing high-performance and reliable metallic products with AM. These challenges often arise from the complexity of the thermal cycles materials undergo during the deposition of successive layers. While this is currently viewed as an inherent downside of AM, it also presents a unique opportunity to engineer the microstructure. The thermal cycles, if effectively harnessed, can serve as an intrinsic heat treatment, triggering desired phenomena such as recrystallization, tempering, and precipitation. Using advanced characterization techniques, the current project aims to provide crucial insights into how we can engineer thermal history and microstructural development during AM to develop reliable, high-performance products.

The project will be conducted in the state-of-the-art research labs at Imperial College London, with potential national and international collaborations with other institutions in the UK, US, Canada, and Australia. Interested applicants should submit a cover letter, their most recent CV, and a list of references to Dr. Haghdadi (n.haghdadi@imperial.ac.uk). Shortlisted candidates will be contacted for further interviews.

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: Dr Cecilia Mattevi 

Applications are invited for a Ph.D. studentship focused on the Aqueous Smart Batteries for Wearable Electronics within the Materials Department at Imperial College London. The market of wearable technologies is rapidly expanding, providing consumers with interconnected and autonomous electronic devices such as smart clothes, activity trackers and wearable cameras. To power this rising number of wearable systems, new battery technologies and manufacturing methods are needed. 3D Printing allows the sustainable fabrication of batteries with arbitrary architectures on small footprint area starting from gel-inks of functional materials, providing an ideal manufacturing platform for wearable batteries.

This research project will focus on the fabrication of self-healable aqueous batteries to be used in wearable electronics. For smart batteries we refer to a battery that can adapt autonomously to an external mechanical stimulus changing their shape. The full battery system will be manufactured by 3D Printing - Robocasting.

The project will involve the formulation of aqueous inks of different materials, the 3D printing of those to form electrodes in different designs. The assembly of a full battery and the electrochemical testing. Structural characterisation using advanced microscopy and tomography methods to determine the microstructure, and to correlate this the performance of the battery.

Advanced spectroscopy characterization will be also utilized to study chemical composition and physical properties of the electrode materials after cycling. Upon device evaluation, the design of the device, and the ink formulation and the material of choice will be revised to optimize the device performance.  State-of-the-art equipment available in Materials Dpt at Imperial will be utilized in this project including a brand-new suite of instruments for electrochemical device studies at South Kensington and White City Campuses.  Applicants should have a keen engagement and solid background in energy storage devices, materials chemistry and materials characterisation. Applications are invited from candidates with (or who expect to gain) a first-class honours degree or an equivalent degree in Materials, Physics, Chemistry, Engineering or a related discipline.

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

The discovery of long-range magnetic order in atomically thin two-dimensional (2D) materials beyond graphene is a new emerging field promising for future applications in ultra-compact low-power spintronics, memory technologies and neuromorphic computing. 2D magnets present unique properties, such as layer-dependent magnetic phases, and they can form moiré patterns by creating a specific rotation angle with an adjacent crystal lattice, giving rise to new electronic and magnetic properties. This project aims at demonstrating new functionalities in moiré superlattices formed by emerging 2D ferromagnetic materials. The project will involve both experimental (Prof. C. Mattevi) and theoretical work (Prof. J. Lischner). Theoretical calculations will be carried out to predict emergent properties of bilayer moiré superlattices with different ferromagnetic monolayer constituents which will be synthesized via MOCVD (metal organic chemical vapour deposition) and then characterised using state-of-the-art techniques, including SQUIDs and magnetic force microscopy.

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: Peter Haynes

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 were demonstrated on six-qubit hardware [3] and machines with over 100 qubits are now available. This project will involve a collaboration with Dr Johannes Lischner in Materials. We will explore quantum embedding as an approach [4] to study localised defects in crystals and apply emerging algorithms for quantum computers such as variational quantum eigensolvers to models parametrised by first-principles simulations on classical computers.

[1] Richard Feynman, Int. J. Theor. Physics 21, 467–488 (1982)
[2] John Preskill, arXiv:1801.00862
[3] Abhinav Kandala et al., Nature 459, 242–246 (2017)
[4] Christian Vorwerk et al., Nat. Comput. Sci. 2, 424 (2022).

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.