Professor Patrick Grant FREng FIMMM
Research interests concern developing understanding the complex underlying physics during materials processing in order to manipulate microstructure, extract maximum economic benefit and impose process control. Much of his research is focused on detailed investigations of novel manufacturing routes and materials utilising liquid droplets, powders and nanomaterials, using a combination of experimentation on large scale facilities, on-line process diagnostics and numerical simulation. All the research work involves close collaboration with industry.
Novel high energy density high reliability capacitors
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 MoD/dstl and a Felix Scholarship)
Processing of oxide dispersion strengthened alloys for fission and fusion power
Z. Hong, M. Gorley, Dr. H. Zhang, 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 EPSRC.
Energy storage for low carbon grids
Dr C. Fu, Professor P.S. Grant
We are developing novel approaches for the fabrication of electrochemical energy storage devices that are relevant to grid-scale energy storage applications as part of the EPSRC Grand Challenge Project: Energy Storage for Low Carbon Grids that is a large scale, multi-partner project led by Imperial College London. We aim to address the many aspects of integrating energy storage into future energy networks. Our current focus is on spray processed electrodes in new materials for grid applications, and we will later apply some of our process developments to battery, fuel cell and device manufacture. Funded by EPSRC.
Microstructural control of Al alloys using intrinsic oxides
A. Verma, Dr. K.A.Q. O'Reilly, Professor P.S. Grant
The world produces 37 million tons of Al every year. All of this metal will have grain refiner additions made to it to promote the nucleation of a fine primary Al grain size. Oxide particles exist in nearly all liquid metals and alloys exposed to air or even under protective atmospheres. Oxide particles are often considered harmful inclusions since they reduce castability of alloy melts, deteriorate ductility and fatigue strength of castings and cause severe difficulties in down stream processing of continuous cast feedstock. As a result, considerable effort is expended to prevent oxide formation and to clean the melt by expensive melt filtering. However, recent research work at Brunel has demonstrated that by liquid metal engineering they can not only eliminate the harmful effects of the oxides but also make positive use of them for effective enhancement of nucleation for structural refinement of the Al grains, so reducing the need for grain refiner additions. Work in Oxford has demonstrated that grain refiner additions not only nucleate the Al grains, but also control intermetallic selection in Al alloys, hence modifying mechanical properties. This project is investigating the potency of oxide particles for heterogeneous nucleation of intermetallics. The nucleation sequence of various intermetallic phases due to unavoidable oxides and their control is being studied during solidification of Al-alloys. A phase extraction technique is being used to facilitate the detailed characterisation of intermetallic phases and their interaction with extrinsic and intrinsic alloy additions. Special reference is being made to inclusions and impurity elements in recycled materials.
Structure-property relationships in graded nanocomposites for microwave applications
Q. Lei, Professor C. Grovenor, Professor P.S. Grant
There has been a great deal of international interest in the exciting electro-magnetic properties that can be achieved in metamaterials but very little work has been undertaken on how to process them in the large volume, techniques required for engineering applications. This project will focus on using a range of microstructural analysis techniques to investigate how the morphology and chemistry of conducting phases in dielectric matrices develop during scalable synthesis techniques, and how these microstructures control the properties. Funded by China Government scholarship and by EPSRC grant EP/I034548. In collaboration with partners in Queen Mary London and Exeter Universities.
The Quest for Ultimate Electromagnetics using Spatial Transformations (QUEST)
Dr C E J Dancer, Dr E Edwards, Prof. C R M Grovenor, Prof. P S Grant
Recent UK-led breakthroughs in the theory of STs, such as the possibilities concerning cloaking and invisibility, have caught both the scientific and popular imagination, and have stimulated a huge growth in related research around the world. The potential of the underlying ST approaches, however, have much wider applicability than cloaking alone, in arguably more important applications that span communications, energy transfer, sensors and security. However, theory and concepts are outstripping practical demonstration and testing, leading to a mismatch in what may be theorised and computed and what can be realised for impact in society and commerce. We contend that the timing is now ideal for UK theorists, modellers, manufacturers and engineers to work together to maintain the UK strength in this field, with a clear focus on the reduction to practice and demonstration of potentially radical new concepts and devices. Collaboration with the University of Exeter, University of St Andrews, and Queen Mary, University of London.
Spray forming of Ni superalloys for high temperature applications
Dr A. Sato, Professor P.S. Grant
We are developing a novel variant of the spray forming process in order to produce Ni superalloy components with enhanced functionality for the power generation industry. Funded by Mitsubishi Heavy Industry, Japan.
Processing and properties of nanocomposite materials for electromagnetic applications
Y. Wang, Professor P.S. Grant
We are using novel processing of polymers to create materials with anisotropic electrical and magnetic properties, and arangeing these according to designs that allow unusual and previously unattainable manipulations of microwaves. Funded by DSTL.
Development of flexible energy storage and generation systems based on nano-hybrid materials
Professor J-M Kim, Professor P.S. Grant
The focus of the research is the development of sub-components and devices for energy storage and environmental energy harvesting based on functional nanostructures and novel fabrication approaches. The core of the research is the exploitation of layer-by-layer approaches for the fine scale arrangement and control of nanomaterials over large areas. This ambitious research builds on key know-how developed in Oxford on LbL processing of suspensions and is directed to both energy storage (primarily supercapacitors) and energy harvesting (piezo-based), and the exploration of processing strategies for their combination in flexible devices. Funded by KETEP, S. Korea.
Modelling and experiments concerning dendrite fragementation
Dr. Z. Guo*, Dr. E. Liotti and Professor P.S. Grant
This project concerns the control of nucleation and subsequent microstructural evolution during solidification by intrinsic grain multiplication using external physical means such as acoustic/shock waves and pulsed magnetic fields. Fragments from broken dendrites are well-known to multiply the number of final grains in a casting, and so provide grain refinement and attendant improvements in quality and performance. The central idea of this project is to enhance dramatically this effect by disrupting continuously the thermal conditions in the melt and at growing solid/liquid interface, without any melt contamination. While various external field approaches have been developed, there remains some uncertainty in the mechanism of dendrite fragmentation, and this project will study both the underlying physics of grain multiplication as well as a new approach for its enhancement. Critical to the work is the use of phase field modelling and fluid flow modelling to explore the conditions that promote grain multiplication. (* Royal Society Newton Fellow, Tsinghua University, China)
EPSRC Centre for Innovative Manufacturing in Liquid Metal Engineering
Dr. E. Liotti, Dr. K. Sundaram, Professor P.S. Grant, Dr. K.A. Q. O'Reilly
Patrick Grant and Keyna O'Reilly have secured funding to establish a new £4.5M EPSRC Centre for Innovative Manufacturing in Liquid Metal Engineering. The Centre is led by BCAST at Brunel University and also involves Birmingham University together with 15 industrial partners who will contribute a further £4.6M. The new EPSRC Centre will work with industrial partners to develop innovative technologies for liquid metal processing that will allow for increased reuse and recycling of metals. This will lead to substantial conservation of natural resources, and a reduction in energy consumption and CO2 emissions. The work at Oxford will be based at the University's Begbroke Science Park, making use of the large scale processing facilities and microstructural characterisation capabilities. Oxford is investigating the nucleation of solid from liquid alloys in advanced solidification processes, and how to control the resulting microstructure to make manufacturing more tolerant to recycled source material. Current projects include the effects of ultrasound and other external fields during solidification and the control of AlFeSi intermetallics.
Bulk nanostructured Al based alloys
H. Begg, Professor P.S. Grant
We are researching fibrular and laminate nanocomposites manufactured either by spray forming, casting, plasma spraying or powder processing, followed by high strain processing by extrusion. Systems of interest are primarily aluminium base and include both ultrahigh strength nanoquasicrystalline alloys ductilised with other Al alloy fibres and immiscible systems. Characterisation includes electron microscopy and X-ray diffractometry. Funded by EPSRC.
Lead free solder development and analysis for aerospace applications
S. Godard-Desmarest, Dr. C. Johnston, Professor P.S. Grant.
Due to safety considerations, the aerospace industry is largely exempt from legislation prohibiting the use of lead in interconnects in electronic assemblies, and lead continues to be used in avionics. This situation is unlikely to continue because of further legislation and difficulties in sourcing lead-containing materials and assemblies from suppliers. In contrast to domestic electronics where lead free solders are now standard and reliable, there are no current widely accepted "drop-in" replacement materials for lead solders that meet the more stringent and hostile aerospace standards for reliability. There is now a pressing need to develop underpinning scientific understanding of the factors governing lifetime of existing and future lead free solder materials for critical aerospace applications. Previous work at Oxford has shown that nanoindentation can be used to measure the mechanical properties and constitutive behaviour of ball grid array solders as a function of temperature, and that with careful interpretation, this data can be used in simulations of stress-strain that in turn can be correlated to reliability performance. The significance of the approach is that unlike previous approaches that have relied on time-consuming and costly mechanical testing of bulk materials to obtain basic property data, the nanoindentation and modelling route offers the potential to identify more rapidly promising lead free alloys that meet aerospace requirements, usually quick methods and very small amounts of candidate materials. The project will build on the approach established at Oxford to study a variety of promising new lead free solder compositions for aerospace applications. Ball grid array joints are made in-house so that full process history data can be captured and reproducibility assured. These assemblies are probed by nanoindentation and the key mechanical behaviour (yield, temperature dependent creep, etc) captured and interpreted in a form suitable for input into a numerical model of stress-strain accumulation. In this way, the potential of alloys can be firstly ranked qualitatively, and then the most promising alloys studied in more detail by further probing and modelling, and thermal cycling or assemblies using equipment at Oxford and at industrial partners. This project is sponsored by EPSRC, Goodrich and Oxatech
Materials Knowledge Transfer Network - Transport and Sustainability
Dr. C. Johnston, Dr. R.M.K. Young, Professor. P.S. Grant
As part of the Materials KTN, we are running a comprehensive network and business programme focused future lightweight and high temperature materials for low pollution, high efficiency transport. New materials, their manufacturing technologies and their integration into engineering systems are critical if UK aerospace, automotive rail and marine sectors are to meet global technical drivers. We are helping UK transport and technology businesses to meet these requirements through a range of scientific and technical products and services focused on: lightweight materials, materials technologies for reduced emission, end of life technologies (disassembly, re-use, recycling), and more electric technologies. We also lead the Sustainability theme within the Materials KTN(Funded by UK Technology Strategy Board)
Nanostructures for energy applications
L. O'Neill, C.A. Huang, M. Jiang, 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.
Development of high performance products comprising dissimilar metals by spray forming
S. Zhao, Professor P.S. Grant
Spray forming is being researched in order to produce clad tubes and cylinders with different interior and external prperties. Critical to these materials is control of the interface between the materials in terms of its strength and toughness, inter-diffusion, phase formation, and response to downstream processing. Successful development of this approach will facilitate a range of unusual products optimised for niche, high value applications in a number of industries. In coolaboration with Dr. J. Mi, University of Hull. Funded by Baosteel, China.
16 public active projects
Scaleable ultra-thin and high power density graphene supercapacitor electrodes manufactured by aqueous exfoliation and spray deposition, B. Mendoza-Sanchez, B. Rasche, V. Nicolosi and P.S. Grant, Carbon, 52 (2013), 337-346. doi:10.1016/j.carbon.2012.09.035
An investigation of nanostructured thin film a-MoO3-based supercapacitor electrodes in an aqueous electrolyte, B. Mendoza-Sanchez, T. Brousse, C. Ramirez-Castro, V. Nicolosi and P.S. Grant, Electrochimica Acta, 91 (2013), 253-260. doi:10.1016/j.electacta.2012.11.127
Influence of cooling rate on the Fe bearing intermetallic formation in an AA6063 Al alloy, A. Verma, S. Kumar, P.S. Grant and K.A.Q. OReilly, J. Alloys and Compounds, 555 (2013), 274-282. doi: 10.1016/j.jallcom.2012.12.077
Nanomechanical characterization of Sn-Ag-Cu joints at elevated temperature. Part 1: Young’s modulus, hardness and deformation mechanism, V.M.F. Marques, C. Johnston and P.S. Grant, Acta Mat., 61 (2013), 2460-2470. doi:10.1016/j.actamat.2013.01.019
Nanomechanical characterization of Sn-Ag-Cu joints at elevated temperature. Part 2: Nanoindentation creep and the relationship with uniaxial creep, V.M.F. Marques, C. Johnston and P.S. Grant, Acta Mat., 61 (2013), 2471-2480. doi:10.1016/j.actamat.2013.01.020
Charge storage properties of MoO3/SWCNT-COOH composite electrode in LiClO4 propylene carbonate, B. Mendoza-Sanchez and P.S. Grant, Electrochimica Acta.doi:10.1016/j.electacta.2013.03.072
An electrochemical microactuator based on highly textured LiCoO2, H. Zhang and P.S. Grant, Sensors and Actuators B: Chemical, 176, (2013), 52-57. doi: 10.1016/j.snb.2012.08.079
Fe bearing intermetallic phase formation in a wrought Al-Mg-Si alloy, S. Kumar, P.S. Grant and K.A.Q. O'Reilly, Trans. Indian Inst. Mat., 65 (2012), 553-557.doi:10.1007/s12666-012-0221-y
A high-speed imaging and modeling study of dendrite fragmentation caused by ultrasonic cavitation, D. Shu, B. Sun, J. Mi and P.S. Grant, Mat. Trans. A., 43 (2012), 3755-3766. doi:10.1007/s11661-012-1188-3
An implicit parallel multigrid computing scheme to solve coupled thermal-solute phase-field equations for dendrite evolution, Z. Guo, J. Mi and P.S. Grant J. Computational Phys., 231 (2012), 1781-1796. doi:10.1016/j.jcp.2011.11.006
An Al-Si-Ti hierarchical metal-metal composite manufactured by co-spray forming, A.J. Kelly, J. Mi, G.V. Sinha, P. Krug, F. Crosa, F. Audebert and P.S. Grant, J. Mat. Proc. Tech., 211 (2011), 2045-2049. doi:10.1016/j.jmatprotec.2011.07.001
The role of nanomaterials in redox-based supercapacitors for next generation energy storage devices, X. Zhao, B. Mendoza Sanchez, P.J. Dobson and P.S. Grant, Nanoscale, 3 (2011), 839-855. doi: 10.1039/c0nr00594k
Fully vacuum-deposited planar heterojunction polymer solar cells, P. Kovacik, G. Sforazzini, A.G. Cook, S. Wllis, P.S. Grant, H.E. Assender and A.A.R. Watt, ACS Appl. Mater. Interfaces, 3 (2011), 11–15. doi: 10.1021/am1008985
A quantitative study of solute diffusion field effects on heterogeneous nucleation and the grain size of alloys, D. Shu, B. Sun, J. Mi and P.S. Grant, Acta Mat., 59 (2011), 2135-2144. doi:10.1016/j.actamat.2010.12.014
Spray forming of bulk ultrafine grained Al-Fe-Cr-Ti, C. Banjongprasert, S.C. Hogg, E. Liotti, C.A. Kirk, J. Mi and P.S. Grant, Mat. Trans. A., 41 (2010), 3208-3215. doi: 10.1007/s11661-010-0386-0
Printable magnetite and pyrrole-treated magnetite based supercapacitors, X. Zhao, C. Johnston, A. Crossley and P.S. Grant, J. Mater. Chem., 20 (2010), 7637-7644. doi: 10.1039/c0jm00028k
Colloidal synthesis of lead oxide nanocrystals and their optoelectronic properties, C.A. Cattley, A. Stavrinadis, R. Beal, J. Moghal, A.C. Cook, P.S. Grant, J.M. Smith, H.E. Assender and A.A.R. Watt, Chem. Comm., 46 (2010), 2802–2804. doi: 10.1039/b926176a.
SnS/PbS nanocrystal heterojunction photovoltaics, A. Stavrinadis, J.M. Smith, C.A. Cattley, A.C. Cook, P.S. Grant and A.A.R. Watt, Nanotechnology, 21 (2010), 185202 (7pp). doi: 10.1088/0957-4484/21/18/185202.
Fabrication and electrical properties of bulk textured LiCoO2, H. Zhang, P.J. Baker and P.S. Grant, J. Am. Ceram. Soc., (2010), doi: 10.1111/j.1551-2916.2010.03634.x
Modelling the deposition dynamics of a twin-atomizer spray forming system, G. Zhang, Z. Li, Y. Zhang, J. Mi and P. S. Grant, Mat. Trans. B, (2010) doi: 10.1007/s11663-009-9333-0
A novel hybrid supercapacitor with a carbon nanotube cathode and an iron oxide/carbon nanotube composite anode, X. Zhao, C. Johnston and P. S. Grant, J. Mater. Chem., 19 (2009), 8755-8760, doi: 10.1039/b909779a
Arc sprayed steel: microstructure in deep substrate features, A.P. Newbery and P.S. Grant, J. Thermal Spray Techn., 18 (2009), 256-271. doi: 10.1007/s11666-009-9300-y
Spray deposition of steam treated and functionalized single and multi-walled carbon nanotube films for supercapacitors, X. Zhao, W. Wang, B.T. Chu, B. Ballesteros, W. Wang, C. Johnston, J.M. Sykes and P.S. Grant, Nanotechnology, 20 (2009), 065605, doi:10.1088/0957-4484/20/6/065605.
Spray deposited fluoropolymer/multi-walled carbon nanotube composite films with high dielectric permittivity at low percolation threshold, X. Zhao, A.A. Koos, B.T.T. Chu, C. Johnston, N. Grobert, P.S. Grant, Carbon, 47 (2009), 561-569. doi:10.1016/j.carbon.2008.10.042.
Spray deposition of polymer nanocomposite films for dielectric applications X. Zhao, C. Hinchliffe, C. Johnston, P.J. Dobson and P.S. Grant, Mat. Sci. Eng. B, 151 (2008), 140–145. doi:10.1016/j.mseb.2008.05.024.
Modelling the shape and thermal dynamics during the spray forming of Ni superalloy rings. Part 1: droplet deposition, splashing and re-deposition J. Mi and P.S. Grant, Acta Mat., 56 (2008), 1588-1596, doi:10.1016/j.actamat.2007.12.021.
Modelling the shape and thermal dynamics during the spray forming of Ni superalloy rings. Part 2: heat flow and solidification, J. Mi and P.S. Grant, Acta Mat., 56 (2008), 1597-1608, doi:10.1016/j.actamat.2007.12.022.
An electrochemical study of repassivation of aluminium alloys with SEM examination of the pit interiors using resin replicas, K.L. Moore, J.M. Sykes and P.S. Grant, Corros. Sci., 50 (2008), 3233-3240. doi:10.1016/j.corsci.2008.08.027.
Pitting corrosion of spray formed Al–Li–Mg alloys, K.L. Moore, J.M. Sykes, S.C. Hogg and P.S. Grant, Corros. Sci., 50 (2008), 3221-3226. doi:10.1016/j.corsci.2008.08.012
The use of interfacial 3D geometry to control stress distributions in W coatings for fusion armour applications, G. Thomas, R. Vincent, G. Matthews, B. Dance and P.S. Grant, Mat. Sci. Eng. A, 477 (2008), 35–42. doi:10.1016/j.msea.2007.05.120
Multiphysics modelling of the spray forming process, J. Mi, U. Fritsching, O. Belkessam, I. Garmendia, A. Landaberea and P.S. Grant, Mat. Sci. Eng. A, 477 (2008), 2–8. doi:10.1016/j.msea.2007.08.083
Solidification in spray forming, P.S. Grant, Mat. Trans. A, 38A (2007), 1520—1529. doi:10.1007/s11661-006-9015-3
Processing, microstructure and property aspects of a spray cast Al-Mg-Li-Zr alloy, S.C. Hogg, I.G. Palmer, L.G. Thomas and P.S. Grant, Acta Mat., 55 (2007), 1885–1894. doi:10.1016/j.actamat.2006.10.057
Optimal robot path for minimizing thermal variations in a spray deposition process, P.D.A. Jones, S.R. Duncan, T. Rayment and P.S. Grant, IEEE Trans. Control Systems Techn., 15 (2007), 1-11. doi:10.1109/TCST.2006.883196
Evolution of percolation properties in nanocomposite films during particle clustering, T.K.H. Starke, C. Johnston and P.S. Grant, Scripta Mat., 56 (2007), 425-428. doi:10.1016/j.scriptamat.2006.10.034.
Microstructure evolution of vacuum plasma sprayed CoNiCrAlY coatings after heat treatment and isothermal oxidation, P. Poza and P.S. Grant, Surf. Coatings Techn., 201 (2006), 2887-2896. doi:10.1016/j.surfcoat.2006.06.001
Scientific, technological and economic aspects of rapid tooling by electric arc spray forming, A. Roche, S.R. Duncan and P.S. Grant, J. Thermal Spray Tech., 15 (2006), 796-801. doi:10.1361/105996306X1468794
The effect of particle distribution inhomogeneities on the dielectric properties of polymer/ceramic films, T.K.H. Starke, C. Johnston, S. Hill, P.D. Dobson and P.S. Grant, J. Phys. D: Appl. Phys., 39 (2006), 1305-1311.
Microstructural characterisation of spray formed Si-30Al for thermal management applications, S. Hogg, A. Lambourne, A. Ogilvy and P.S. Grant, Scripta Mat., 55 (2006), 111-114.
Oxidation during the electric arc spray forming of steel, A.P. Newbery and P.S. Grant, J. Mat. Processing Techn., 178 (2006), 259-269.
An investigation of novel spraycast Al-Mg-Li-Zr-(Sc) alloys, S.C. Hogg, I.G. Palmer and P.S. Grant, Mat. Sci. Forum, 519-521 (2006), 1629-1633.
Applied periodic l-infinity control: presenting prototype designs for a real spray form tooling process, V.A. Tsachouridis, P.D.A. Jones, S.R. Duncan and P.S. Grant, Control Eng. Practice, 14 (2006), 1477-1493.
Modelling the heat flow in spray formed steel shells for tooling applications, T. Rayment and P.S. Grant, Met. Mat. Trans. B, 37B (2006), 1037-1047.
Materials for fission and fusion power
S G Roberts / A J Wilkinson / P Bagot / P S Grant
Do you want to help to solve the future energy crisis? Are you interested in doing novel and exciting experimental work? Would you like opportunities for international collaborations and travel?
Fusion reactors potentially offer a complete solution to the problem of future energy supply, and are environmentally friendly: they emit no greenhouse gases, and so would not contribute to global warming. The recent success of the JET project at Culham in the south of Oxfordshire, which proved that plasma could be heated and controlled to produce fusion, has demonstrated the feasibility of the concept. The next step is to construct a prototype reactor (ITER) which is now the focus of a major international project. This will be followed by a prototype commercial reactor (DEMO).
So far relatively little demand has been made on the properties of the materials used for JET and other prototype reactors, since they had only to contain an operating plasma for very short times. For actual fusion power plants, materials issues will be crucial to success.
In the closer future, advanced fission reactors will be needed to meet some at least of the world energy demand, as fossil stocks dwindle and as their use become less environmentally acceptable. Materials degradation by radiation damage is a serious issue in current-generation reactors, and the new “generation IV” reactors currently being proposed will place even heavier demands on materials.
The materials needed will operate at temperatures of 600ºC or more, will need to withstand stresses up to 300MPa, and will accumulate over their lifetime radiation damage from fast neutrons amounting to ~100 displacements per atom. In fusion reactors, an additional problem will arise due to the high levels of helium and hydrogen produced in transmutation reactions. It is essential that any material used maintains adequate strength and toughness, while suffering minimal dimensional change through swelling and creep. These are very demanding requirements, which cannot be met by conventional structural materials. It will be necessary to develop and evaluate new materials.
Ion irradiation is currently the only non-activating method of mimicking the fast neutron damage produced in nuclear fission and fusion reactors (with or without co-implantation with He or H, to mimic the effects of fusion by-products). Implanted layers are ~2-3 microns deep or less. We have developed micromechanical test methods, using ion beam machining to make specimens only a few microns in size, for determination of the elastic, plastic and fracture properties of candidate materials. This is linked with parallel electron microscopy and atom-probe microscopy studies of the development and nature of the radiation damage, and of the interactions between radiation damage and mobile dislocations which give rise to hardening and embrittlement.The experimental work is closely linked to the development and verification of computer models of radiation defects and their interactions.
A new large research project in this area, an EPSRC programme grant centred at Oxford University, started in early 2010. It involves UK and European partners (especially Liverpool University, CCFE Culham laboratory, the Commissariat à l'Énergie Atomique (CEA), and Rolls Royce). It aims at providing a thorough understanding of the mechanical properties and irradiation response of materials with potential for fusion and advanced fission reactor applications, including low-activation ferritic-martensitic steels, oxide-dispersion strengthened steels, model Fe-Cr alloys and tungsten alloys.
Individual research student projects started in 2009, 2010 and 2011 in the areas of:
- Tungsten-based alloys,
- Radiation hardening and embrittlement,
- Grain boundary irradation embrittlement,
- Grain boundary stress-corrosion cracking,
- Processing & properties of Oxide Dispersion Strengthened alloys
Applications for studentships in these areas from well-qualified applicants of all nationalities are welcome, but note that all funded projects for 2012 start have now been allocated
Spray forming of hierachical metal-metal composites
P S Grant
Spray forming is a high technology casting process for producing large scale advanced alloys with unmatched quality and performance. This project will explore spray forming for the processing of 'designer' alloys by co-spraying a second (or more) liquid or metal phase into the primary sprayed alloy so that co-deposition and mixing occur to produce unusual and potentially highly useful structures and properties. This project will make use of the leading spray forming facilities at Oxford to manufacture and study hierachical metal-metal composites in which microstructural features at the nano, micro and meso scale controlled separately by co-spraying of different materials, from the simplest mixture of two pure metals that are then heavily deformed to produce nanofibrils, through to the co-injection of nanoscale powders and mixing of different liquid sprays to produce in-situ reactions and otherwise difficult to process compositions and phases. The microstructure and mechanical properties will be studied for the most promising combinations, together with the effect of downstream processing operations.
Also see homepages: Patrick Grant
Ultra high speed imaging of microstructural instability under external manipulation
P S Grant, E Liotti
Also see homepages: Patrick Grant
Novel processing of nanostructured films for energy storage
P S Grant
A new method for manufacturing electrodes for Li ion batteries, electrochemical supercapacitors and permeable fuel cell membranes has been developed in Oxford based on the spray deposition of suspensions of nanomaterials. The next stage in the evolution of this new process is to move from proof of concept to exploring the possibilities of manufacturing new energy storage devices with outstanding performance. The research will investigate how to produce designed meso-structures and hybrid electrodes involving novel combinations of: (i) engineered porosity for ion mobility, (ii) conductors for electron mobility, (iii) interfacial nanostructure for efficient charge transfer, and (iv) nanostructuring of electrochemical active materials for high surface area, storage capacity and strain tolerance. The project will involve a combination of processing and equipment development, microstructural characterisation and energy storage measurements.
Also see homepages: Patrick Grant
Also see a full listing of New projects available within the Department of Materials.