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Patrick Grant

Professor Patrick Grant FIMMM FREng
Vesuvius Chair of Materials
Head of Department

Department of Materials
University of Oxford
16 Parks Road
Oxford OX1 3PH
UK

Tel: +44 1865 273737 (Head of Dept Office)
Tel: +44 1865 283763 (Begbroke Office)
Tel: +44 1865 273777 (reception)
Fax: +44 1865 848785 (Begbroke fax)

Research Group Homepage

Summary of Interests

My research takes place at the interface between advanced materials and manufacturing, and concerns a wide range of structural and functional materials. Current applications include structured porous electrodes for supercapacitors and batteries, 3D printed materials with spatially varying electromagnetic properties for microwave devices, and advanced metallics for power generation. Recent work has also concerned X-ray imaging of microstructural evolution, especially of solidifying alloys.

The research uses variants of manufacturing techniques used in industry such as vacuum plasma spraying and field assisted sintering alongside in-house developed novel processes such as spray deposition of multi-suspensions and 3D printing of dielectric materials. We make extensive use of numerical modelling for device design, to provide insights into underlying processs physics, and to understand how heat and mass flows relate to the final microstructure. All the research work involves close collaboration with industry and other universities across the UK and the world.

Find out more: Group research page

Current Research Projects

Novel high energy density high reliability capacitors
Dr. A. Mahadevegowda, Dr. C. Johnston, Dr. H.E. Assender, Professor P.S. Grant
Current capacitor technology significantly limits the temperature capability and electrical performance of power electronics relative to the "More Electric Airframe" systems requirements, which are emerging rapidly as a key priority for both aeroengine and airframe manufacturers. Novel capacitor materials combining high dielectric ceramics and high performance polymers are being developed for aero-engine applications, particularly within the more electric aircraft concept. Investigations include characterisation of the fundamental material properties using advanced analytical instruments, clean room characterisation of the electrical properties, development of fabrication routes, and modelling of behaviour for lifetime prediction. (Funded by Technology Strategy Board, Labinal Power, ICW Ltd)

Processing and properties of tungsten coatings for fusion reactors
E. Rowe, Dr D. Armstrong, Professor P.S. Grant
Tungsten is the key plasma facing material for use in any future nuclear fusion device due to its high melting point, good sputter resistance and low activity. However its refractory nature leads to inherent difficulties in its processing and many traditional production routes are not available. Vacuum plasma spraying is one of the most attractive methods of producing tungsten coatings for this application, but thermal mis-match between the tungsten and substrates such as steel or copper lead to the development of complex residual stresses which degrade the performance of the coating. Other challenges include microstructural control, and characterising the properties of tungsten in the coating arrangement. This project will use recently upgraded vacuum plasma spraying equipment to produce both pure and alloyed tungsten coatings on novel substrates. In-situ process data will be recorded including temperatures, deflections, etc. Coatings will be characterised using state of the art microscopy and micro-mechanical testing facilities, as well as thermal loading, and finite element analysis used to understand the evolution of the stress state. By consideration of the process conditions in manufacture, the microstructure and the properties of the coatings, optimisation will be performed to produce practical tungsten coatings for further testing and application. Funded by EPSRC and CCFE

Porosity control of Al alloys using inclusions
J. Malisano, Dr. K.A.Q. O'Reilly
The world produces 37 million tons of Al every year. All of this metal will contain inclusions. The overall aim of this project is on the formation of porosity in Al alloys, focussing specifically on elucidating the role of inclusions, which are known to act synergistically with hydrogen in solution as the impetus for porosity formation during solidification. The most widely used industrial approach for testing the "porosity potential" of a melt is the Reduced Pressure Test (RPT), which measures a convolution of both the inclusion content and hydrogen content together. The RPT exacerbates the size of porosity, and the pores are more easily examined, by eye or with X-ray Computed Tomography (XCT). 

Processing of oxide dispersion strengthened alloys for fission and fusion power
Sarah Connolly, Professor S.G. Roberts, Professor P.S. Grant
Oxide dispersion strengthened alloys comprise a metallic alloy with a dispersion of sub-micron oxide particles. The fine scale dispersion of the ceramic particles gives rise to strain fields around the particles, which can confer strength and other properties by interaction with dislocations in a manner similar to that of fine scale precipitates produced by ageing heat treatments in conventional metallurgical alloys. The particles also have the potential to stabilize microstructural features such as grain size at intermediate temperature. A further potential benefit of these particles in steels for nuclear applications is that they or the interface between the particles and the matrix may act as a 'sink' for vacancies and He induced by a neutron flux environment, partially mitigating otherwise severely damaging effects such as embrittlement. It is known that the type (size, volume fraction, chemistry, etc) of particles and the homogeneity of their dispersion in the matrix is influential on the final ODS alloy properties and the extent to which potential benefits are realised in practice. However, there are few systematic studies that allow the detail of the oxide particle mixing/dissolution and re-precipitation behaviour to be reconciled in terms of the processing parameters of practical interest. In part, this derives from the long times associated with the design-make-characterise-irradiate-test cycle. In this project we combine in-house processing of high quality ODS steel powders by mechanical means, the subsequent manufacture of consolidated ODS alloys. The study focusses on the dynamics of the critical metallic-ceramic mixing process and aims to develop ideas for identifying and assuring the "quality" of milled powders so that downstream properties are evolved optimally. Alternative processes to mechanical mixing are also being explored. Funded by the National Nuclear Laboratory and EPSRC.

Liquid Metal Engineering (LiME) EPSRC Manufacturing Hub - Oxford spoke
S. Feng, A. Lui, Dr. E. Liotti, Professor P.S. Grant
The group is a partner in a new Engineering and Physical Sciences Research Council (EPSRC) funded £10 million Manufacturing Research Hub, which started in November 2015. The EPSRC Manufacturing Hub in Future Liquid Metal Engineering is led by Brunel University with major research activities at Oxford, Leeds, Manchester and Imperial College London, and involves a large number of industrial partners who will invest a further £45 million over the next 7 years. The UK metal casting industry adds £2.6bn/yr to the UK economy, employs 30,000 people, produces 1.14 million tons of metal castings per year and underpins the competitive position of every sector of UK manufacturing. However, the industry faces severe challenges, including increasing energy and materials costs, tightening environmental regulations and a short supply of skilled people. The group research will develop new approaches to X-ray imaging of solidification, including machine-learning techniques for automated image analysis. These techniques will be used to understand how impurities in liquid metals control microstructural evolution and how solidification conditions can be manipulated, for example by a pulsed magnetic field, to improve the tolerance of processes to impurities and so enable the increased re-circulation of metals in the manufacturing economy.

Nanostructures for energy storage applications
Dr C.A. Huang and Professor P.S. Grant
Nano-structured materials are attractive for some energy related applications because they can provide very high surface areas per unit mass, leading to high energy densities in various storage applications. A supercapacitor (electrochemical capacitor) stores electrical energy either in the form of ions at an electrode/electrolyte interface (electrical double-layer capacitor, EDLC) or by faradic redox reactions at the electrode (pseudo-capacitors). Both types offer high power density (rapid discharge), excellent reversibility, and long cycle life. Supercapacitors usually use activated (meso-porous) graphite for their electrodes, but alternatives with higher power capability are being studied intensively, including entangled, meso-porous carbon nanotube (CNT) films - an application that makes use of the "natural" tendency of the CNTs to entangle and percolate current at low volume fractions. We are fabricating comparatively large amounts of both multi-walled CNTs (by chemical vapour deposition) or single wall CNTs (by arc discharge) in-house, purifying them, functionalizing their surface to improve their ion storage capability, and then processing them into large area films or buckypaper - on a variety of flexible or stiff substrates. In some cases, other process steps can add nanoparticles to provide a superimposed pseudo-capacitance. Our goal is to demonstrate the potential benefits of this approach over existing materials at the laboratory scale, and also to ensure that we develop processing technologies that at all stages offer the potential for cost-effective scaling to the near-industrial, and then full industrial use. The ability to process and characterize fully these materials in-house is key to this strategy. Funded by EPSRC Grant: Supergen Energy Storage.

Powder of dispersion strengthened copper alloys for fusion applications
A. Morrison, Professor P.S. Grant
Nanostructured oxide dispersion strengthened (ODS) copper alloys with a high density of nano-sized dispersoids exhibit high thermal conductivity, excellent irradiation resistance, high temperature microstructural stability, which makes them promising candidates as heat sink materials in nuclear power generation. Processing plays an important role in determining performance because the stabilising, fine-scale nano-clusters of ceramic particles are developed during the early stages of processing and cannot be subsequently manipulated. The objectives of our work are to develop an in-house manufacturing capability for Cu ODS alloys, in which powder metallurgy and spray forming will be two key processing techniques. These primary processing approaches are being developed as an alternative to the commercial in-situ oxidation route during casting and heat treatment. The primary processing will be complemented by spark plasma sintering consolidation processing to ensure full density. At each stage the nano/micro-structure will be investigated using a range of microstructural techniques, both in Oxford and at the new Materials Research Facility at CCFE. This information will be used to rationalise the mechanical response of alloys assessed by a combination of conventional and micro-mechanical testing, with the aim identifying the process-material combinations that provide optimum mechanical properties and microstructural stability. Funded by CCFE and EPSRC.

7 public active projects

Research Publications

Solid-state supercapacitors with rationally designed heterogeneous electrodes fabricated by large area spray processing for wearable applications, C. Huang, J. Zhang, N.P. Young, B. Chen, H.J. Snaith, I. Robinson and P.S. Grant,Sci. Rep.6 (2016), 25684.

Preparation, microstructure and microwave dielectric properties of sprayed PFA/barium titanate composite films,Q. Lei, C. Dancer, P.S. Grant and C.R.M. Grovenor, Comp. Sci. Tech.129 (2016), 198–204.

Evolution of Fe bearing intermetallics during DC casting and homogenization of an Al-Mg-Si Al Alloy, S. Kumar, P.S. Grant and K.A.Q. O'Reilly, Mat. Trans. B47A (2016), 3000-3014.

Microwave dielectric characterisation of 3D-printed BaTiO3-ABS polymer composites, F. Castles, D. Isakov, A. Lui, Q. Lei, C.E.J. Dancer, Y. Wang, J.M. Janurudin, S.C. Speller, C.R.M. Grovenor and P.S. Grant, Sci. Rep.6 (2016), 22714.

Gap corrected thin film permittivity and permeability measurement with a broadband coaxial line technique, Y. Wang, I. Hooper, E. Edwards and P.S. Grant, IEEE Trans. Microwave Theory Techn.64 (2016), 924-930.

Production of hollow and porous Fe2O3 from industrial mill scale and its potential for large-scale electrochemical energy storage applications, C. Fu, A. Mahadevegowda and P.S. Grant, J. Mat. Chem. A4 (2016), 2597-2604.

3D printed anisotropic dielectric composite with meta-material features, D.V. Isakov, Q. Lei, F. Castles, C.J. Stevens, C.R.M. Grovenor and P.S. Grant, Materials & Design93 (2016), 423–430.

Mapping of multi-elements during melting and solidification using synchrotron X-rays and pixel-based spectroscopy, E. Liotti, A. Lui, T. Connolley, M. Wilson, M. Veale, K. Sawhney, I. Dolbnya, A. Malandain and P.S. Grant,Sci. Rep.5 (2015), 15988.

Fe3O4-carbon nanofibre bead-on-string electrodes for enhanced electrochemical energy storage, C. Fu, A. Mahadevegowda and P.S. Grant, J. Mat. Chem. A3 (2015), 14245–14253.

Processing and microstructure characterization of oxide dispersion strengthened Fe–14Cr–0.4Ti–0.25Y2O3 ferritic steels fabricated by spark plasma sintering, H. Zhang, K. Dawson, H. Ning, C.A. Williams, M. Gorley, C.R.M. Grovenor, S.G. Roberts, M.J. Reece, H. Yan and P.S. Grant, J. Nucl. Mat.464 (2015), 61-68.

Real-time synchrotron X-ray observation of equiaxed solidification of aluminium alloys and implications for modelling , A. Prasad, E. Liotti, S.D. McDonald, K. Nogita, H. Yasuda, P.S. Grant and D.H. StJohn, MCWASP, IOP Conf. Series: Mat. Sci. Eng.84 (2015), 012014.

Characterisation of the residual stresses in spray formed steels using neutron diffraction, T.L. Lee, J. Mi, S.L. Zhao, J.F. Fan, S.Y. Zhang, S. Kabra and P.S. Grant, Scripta Mat.100 (2015), 82-85.

Enhancing the supercapacitor behaviour of Fe3O4/FeOOH coaxial nanowire-carbon nanotube hybrid electrodes in aqueous electrolytes, L. O'Neill, C. Johnston and P.S. Grant, J. Power Sources274 (2015), 907–915.

Projects Available

*/**X-ray video imaging and machine learning to understand alloy solidification
Prof Patrick Grant / Dr Enzo Liotti

We have developed X-ray imaging equipment and experimental approaches to record real-time videos of the solidification of alloys with high temporal and spatial resolution. This technique is providing new information to help understand and resolve long-standing and important issues in solidification science, including the role of grain refiners, impurities, external fields and many other important practical parameters. The particular novelties developed in the group include: (i) the ability to apply a highly controlled and reproducible pulsed electromagnetic field during solidification to break-up dendrites and to mimic industrial processes; (ii) the use of new multi-element detector (with STFC) that allows the investigation of more complex composition, realistic alloys; and (iii) a range of image analysis techniques including state-of-the-art pattern recognition machine learning algorithms (with Engineering Science) that allow quantified data to be extracted from videos automatically. This project will exploit and further develop these capabilities to study and quantify the nucleation and growth behaviour of equiaxed grains during commercial casting practices. The work will involve X-ray imaging solidification experiments, microstructural analysis and computer programming for automated analysis of images and videos. The project will also require travel and stays of typically 5 days to X-ray synchrotron sources around the world, particularly the Diamond Light Source (UK), ESRF and Soleil (Grenoble and Paris, France) and the Swiss Light Source (Geneva, Switzerland). This project is in collaboration with the EPSRC Future Manufacturing Hub - Liquid Metal Engineering

Candidates are considered in the January 2018 admissions cycle which has an application deadline of 19 January 2018.  

This 3.5-year EPSRC DTP studentship will provide full fees and maintenance for a student who has home fee status (this includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study).  The stipend will be at least £15,553 per year.  Other EU students should read the guidance at http://www.materials.ox.ac.uk/admissions/postgraduate/eu.html for further information about eligibility.

Any questions concerning the project can be addressed to Professor Patrick Grant (patrick.grant@materials.ox.ac.uk).  General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk.  You must complete the standard Oxford University Application for Graduate Studies.  Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Patrick Grant

Novel manufacturing routes for solid state batteries
Prof Patrick Grant

New ideas for manufacturing the electrodes used in solid state Li ion batteries will be investigated in order to produce improvements in one or more of energy density, power density, cycle life, safety and reduced cost. The research involves developing new ideas and equipment for layer-by-layer, 3D printing, patterning and other types of fabrication for the various parts of a solid-state battery, with each layer optimised for its specific function and location in the device. For example, using layer-by-layer processing to adjust the electrode microstructure progressively during fabrication to improve ion mobility from place to place in the electrode, and to reduce charge and discharge times for electric vehicle applications. The project will involve a combination of novel processing and equipment development, modelling of battery behaviour, detailed microstructural characterisation and energy storage measurements.

 

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Manufacture, characterisation and properties of coatings for nuclear power applications
Prof Patrick Grant

Next generation fusion and fission reactors require a combination of neutron irradiation, temperature and corrosion resistance unavailable from current commercial alloys. Two coating approaches have emerged for materials use in these environments that will be explored in this project. First, to stabilise the microstructural features of alloys for use in fusion or fission applications (e.g. Cu, Fe and W based), such as grain size, a low fraction but very high number density of stable ceramic nano-particles are introduced, to form oxide dispersion strengthened (ODS) alloys. These particles are also effective in acting as sinks for vacancies and He formed by neutron damage, helping to prolong useful lifetime and properties. However, ODS alloys are expensive to manufacture into engineering structures and therefore we will explore the feasibility of applying ultra-thick (1 mm) ODS alloy coatings, using vacuum plasma spraying (VPS), as an alternative to bulk alloy manufacture. The second approach (which can be combined with the first) is to "armour" structural components, usually made from Cu or Fe based alloys just behind the first wall of fusion devices, with a low load carrying, sacrificial refractory metal (e.g. W) ultra-thick coating. Here the challenge is to manage the differential thermal expansion between coating and substrate during thermal cycling of the device, which will be addressed using micro-patterned or sculptured substrates. Large scale manufactriuring research will be combined with modelling of thermal stresses, microstructural characterisation and performance assessment.

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3D printing and additive manufacturing approaches for microwave metamaterials
Prof Patrick Grant

Meta-materials are artificial materials that have properties unavailable from single material classes or composites and have been demonstrated in the lab to enable physical phenomena as cloaking, invisibility, advanced communications, energy transfer, sensors and security. Many of the novel properties of meta-materials involve their unusual interactions with electromagnetic radiation such as light and microwaves. However, theorectical designs with meta-materials are outstripping practical demonstration and testing, and there is an urgent need and exciting opportunity to develop new processing approaches to fabricate new, practical meta-materials for engineering applications.

This project focuses on new processing approaches to build active meta-materials with graded dielectric and magnetic properties using 3D printing. An active meta-material is one that can be switched or controlled using an external stimulus such as electricity, magnetism, light, etc, and are at the early stages of development. The project will develop a number of active meta-material ideas suitable for our in-house 3D printing facility, and then design novel arrangements of these materials to make functioning demonstrators at the 5 - 15 cm scale for measurement. The work will involve interaction with designers using simulations and specialists in measurements in the mega-gigahertz range. At all stages, a key aspect will be to characterise the microstructure and performance of the feedstock materials you have developed. The project will also involve developing novel implementations of the additive manufacture process itself in order to allow 3D active devices to be fabricated.

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Bulk superconducting MgB2 magnets for biomedical applications
S C Speller / C R M Grovenor / P S Grant

Magnetic Resonance Imaging (MRI) is a very widely used technique for medical diagnosis, but the current instruments based on superconducting solenoids are large and expensive. There are emerging designs for much smaller and cheaper instruments for knees, elbows, wrists etc based on bulk superconductors acting as permanent magnets. Permanent magnets also have potential applications in novel drug delivery systems. Magnesium diboride (MgB2) is a possible new material to use in this application. This project will focus on firstly the fabrication of bulk MgB2 materials using the Field Assisted Sintering Technique (FAST), which may offer significant benefits over conventional hot pressing. Working jointly in the Oxford Centre for Applied Superconductivity (www.cfas.ox.ac.uk) and the Processing of Advanced Materials group (users.ox.ac.uk/~pgrant), the student will be involved in powder processing of the precursor material, the design of processing conditions, and understanding the critical links between final microstructure and superconducting properties, with the aim of optimising the magnetic field that can be trapped in the smallest possible volume. This student will be involved with a new EPSRC-funded project in collaboration with Cambridge University, RAL and industrial partners at Element Six, providing opportunities to access industrial processing facilities and to integrate their material with test devices in the Institute for Biomedical Engineering.

Also see homepages: Patrick Grant Chris Grovenor Susannah Speller

Also see a full listing of New projects available within the Department of Materials.