Personal Homepages

Richard Todd

Professor Richard Todd
Professor of Materials

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

Tel: +44 1865 273718 (Room 276.40.23)
Tel: +44 1865 273777 (reception)
Fax: +44 1865 273783


Summary of Interests

Mechanical properties and processing of ceramics and metals. Current interests include processing and properties of ceramic nanocomposites, the use of carbon nanotubes and graphene in ceramic composites, mechanical testing and stress measurement in ceramics at the microscale, high strain rate performance of ceramics for armour applications, "flash sintering" of ceramics, probing of stress and structure using neutrons and synchrotron radiation, improved metal forming for automobiles and mechanisms of superplastic deformation.

  • Pfeil Award of the Institute of Materials 2001, for published work in ceramics.
  • Verulam Medal and Prize of the Institute of Materials, Minerals and Mining 2012, in recognition of distinguished contributions to ceramics.
  • Senior Editor of the Journal of the European Ceramic Society, 2011-present.
  • Fellow of the European Ceramic Society (ECERS), 2013

Current Research Projects

Surface effects in superplastic deformation
M.A. Rust, Dr. R.I. Todd
The superplastic deformation of aluminium and Sn-Pb alloys is being studied with particular reference to surface observations. FIB is being used to etch submicron reference grids on the surface and EBSD is being used to characterise grain boundaries of interest. Aspects being studied include the origin of surface ridges and other inhomogeneous aspects of flow, co-operative grain boundary sliding, intragranular deformation and the nature of grain boundaries. (In collaboration with Superform Metals)

Carbon nanotube reinforced ceramics
Dr. F. Dillon, G. Otieno, Professor R.I. Todd, Professor N. Grobert
There have been several attempts recently to make ceramic nanocomposites in which the reinforcing phase consists of carbon nanotubes. None has resulted in a viable composite, either because the nanotubes have been destroyed by the high firing temperatures used, or because the nanotubes have not been properly dispersed in the ceramic matrix. We are trying to solve these problems using a variety of techniques and using both single- and multi-walled nanotubes. (Supported by The Royal Society, and ERC Starting Grant)

Oxide Nanocomposites
A. Mukhopadhyay, Dr. R.I. Todd
Work in Oxford has shown that alumina/SiC nanocomposites offer enormous improvements in resistance to severe wear compared with pure alumina. Commercial takeup of these materials has been limited, however, owing to the requirement to sinter these materials in inert gas in order to prevent oxidation of the SiC. Routes for producing 100% oxide nanocomposites are being explored that will avoid this problem.

Plasticity in oxide nanocomposites
D. Shi, Dr. R.I. Todd
Alumina/SiC nanocomposites exhibit much more surface plasticity and much less brittle fracture than pure alumina when subjected to severe grinding. This project is investigating the extent to which this also applies to bulk deformation of MgO based nanocomposites.

Understanding and Improving Ceramic Armour
Dr. C.E.J. Dancer, H. Curtis, S. Bennett, S. Falco*, S. Huang**, Dr. S. Ghosh**, Dr. H. Wu**, Dr. B. Vaidhyanathan**, Professor J. Binner**, Dr. N. Petrinic*, Dr. R.I. Todd
Ceramic materials are used for both personnel and vehicle armour since they can be very effective at stopping ballistic projectiles by breaking and eroding them. However, such armour is generically fairly heavy and does not have multihit capability due to its fragmentation during impact. The development of new ceramics for armour is further hindered by the limited understanding of the mechanisms involved in their success and therefore what the characteristics of the ideal ceramic should be. We are taking a holistic approach to this problem, by combining modelling and experimental studies on traditional monolithic and novel nanocomposite ceramics. Testing a range of ceramics with systematically differing characteristics will give comparative information about which microstructural features and mechanical properties successful ceramics possess, as well as enabling the development of a fundamental understanding of the high strain rate performance. This will then be used to produce armour with improved properties. (*Department of Engineering, University of Oxford; **Department of Materials, Loughborough University)

5 public active projects

Research Publications

Zapata-Solvas, E., Bonilla, S., Wilshaw, P.R. and Todd, R.I. (2013). ‘Preliminary investigation of flash sintering of SiC’, Journal of the European Ceramic Society 33(13-14) 2811–2816.

Binner, J., Ghosh, S., Huang, S., Vaidhyanathan, B., Wu, H., Brown, P., Dancer, C.E.J., Falco, S., Gerlach, R., Lopez Lopez, E., Petrinic, N. and Todd, R.I. (2013). “Bullet Proof” (Feature Article), Materials World 21(5) 26-29.

Falco, S., Dancer, C.E.J., Todd, R.I. and Petrinic, N. (2013). ‘A new anisotropic constitutive model for ceramic materials failure’, Ceramic Engineering and Science Proceedings 33(10) 93-103.

Fu, Z., Huang, L., Zhang, J. and Todd, R.I. (2012). ‘Ultra-fast densification of CNTs reinforced alumina based on combustion reaction and quick pressing’, Science China Technological Sciences 55, 484-489.

Durrell, J.H., Dancer, C.E.J., Dennis, A., Shi, Y., Xu, Z., Campbell, A.M., Babu, N.H., Todd, R.I., Grovenor, C.R.M. and Cardwell, D.A. (2012). ‘A trapped field of >3 T in bulk MgB 2 fabricated by uniaxial hot pressing’, Superconductor Science and Technology 25(11) 112002.

Yahya, N.A. and Todd, R.I. (2012). ‘Influence of C doping on the fracture mode and abrasive wear of Al2O3’, Journal of the European Ceramic Society 32(16) 4003–4007.

Dancer, C.E.J., Achintha, M., Salter, C.J., Fernie, J.A. and Todd, R.I. (2012). ‘Residual stress distribution in a functionally graded alumina–silicon carbide material’, Scripta Materialia 67(3) 281–284.

Mukhopadhyay,  A., Otieno, G., Chu, B.T.T., Wallwork, A., Green, M.L.H. and Todd, R.I (2011). ‘Thermal and electrical properties of aluminoborosilicate glass-ceramics containing multiwalled carbon nanotubes’, Scripta Mater. 65(5) 408-411.

Dancer, C.E.J., Curtis, H.M., Bennett, S.M., Petrinic, N. and Todd, R.I. (2011). ‘High strain rate indentation-induced deformation in alumina ceramics measured by Cr3+ fluorescence mapping’, J. Eur. Ceram. Soc. 31(13) 2177–2187.

Rust, M.A. and Todd, R.I. (2011). ‘Surface Studies of Superplasticity in Al5083: Confirmation of Diffusion Creep and Grain Neighbour Switching’, Acta Mater. 59(13) 5159-5170.

Guo, S. and Todd, R.I. (2011). ‘Quantitative Optical Fluorescence Microprobe Measurements of Stresses around Indentations in Al2O3 and Al2O3/SiC Nanocomposites: The Influence of Depth Resolution and Specimen Translucency’, Acta Mater. 59(7) 2637-2647.

Mukhopadhyay, A. and Todd, R. I. (2011). ‘Relationship between microstructure and abrasive wear resistance of Al2O3–FeAl2O4 nanocomposites produced via solid-state precipitation’, J. Eur. Ceram. Soc. 31(3) 339-350.

Sheng, G., Limpichaipanit, A. and Todd, R.I. (2011). ‘High resolution optical microprobe investigation of surface grinding stresses in Al2O3 and Al2O3/SiC nanocomposites’, J. Eur. Ceram. Soc. 31 (1-2) 97-109.

Shapiro, I.P., Todd, R.I., Titchmarsh, J.M. and Roberts, S.G. (2011). ‘An indentation model for erosive wear in Al2O3/SiC nanocomposites’, J. Eur. Ceram. Soc. 31(1-2) 85-95.

Marquis, E.A., Yahya, N.A., Larson, D.J., Miller, M.K. and Todd, R.I. (2010). ‘Probing the improbable: imaging C atoms in alumina’, Materials Today 13(10) 34-36. 

Dancer, C.E.J., Prabhakaran, D., Crossley, A., Todd, R.I. and Grovenor, C.R.M. (2010). ‘The effects of attrition and ball milling on the properties of magnesium diboride’, Supercond. Sci. Technol. 23(6) 065015. 

Mukhopadhyay, A. and Todd, R.I. (2010). ‘Effect of yttria doping on the microstructure and mechanical properties of Al2O3–FeAl2O4 nanocomposites developed via solid state precipitation’, J. Eur. Ceram. Soc. 30(14) 2905-2915. 

Guo, S. and Todd, R.I. (2010). ‘Cr3+ microspectroscopy measurements and modelling of local stress variations in surface grinding stresses in polycrystalline alumina’, J. Eur. Ceram. Soc. 30(12) 2533-2545. 

Otieno, G., Koos, A.A., Dillon, F., Wallwork, A., Grobert, N. and Todd, R.I. (2010). ‘Processing and properties of aligned multi-walled carbon nanotube/aluminoborosilicate glass composites made by sol–gel processing’, Carbon 48(8) 2212-2217 (Article selected by Elsevier as a demonstration “Article of the Future”. Also Figure from this paper was chosen as the cover picture for Carbon 48(10), 2010). 

Zhang, J.Y., Meng, F.C., Todd, R.I. and Fu, Z.Y. (2010). ‘The nature of grain boundaries in alumina fabricated by fast sintering’, Scripta Mater. 62(9) 658-661. 

Mukhopadhyay, A., Chu, B.T.T., Green, M.L.H. and Todd, R.I. (2010). ‘Understanding the mechanical reinforcement of uniformly dispersed multiwalled carbon nanotubes in alumino-borosilicate glass ceramic’, Acta Materialia 58(7) 2685-2697. 

Mukhopadhyay, A. and Todd, R.I. (2010). ‘Microstructure and mechanical properties of Al2O3 matrix nanocomposites produced by solid state precipitation’, J. Eur. Ceram. Soc. 30(6) 1359–1372. 

Guo, S. and Todd, R.I. (2010). ‘Confocal fluorescence microscopy in alumina-based ceramics: where does the signal come from?’, J. Eur. Ceram. Soc. 30(3) 641–648. 

Dancer, C.E.J., Prabhakaran, D., Ba?o?lu, M., Reece, M., Todd, R.I. and Grovenor, C.R.M. (2009). ‘Fabrication and properties of dense ex situ magnesium diboride bulk material synthesized using spark plasma sintering’, Supercond. Sci. Technol. 22(9) 095003.

Limpichaipanit, A. and Todd, R.I. (2009). ‘The relationship between microstructure, fracture and abrasive wear in Al2O3/SiC nanocomposites and microcomposites containing 5 and 10% SiC’, J. Eur. Ceram. Soc. 29(13) 2841–2848. 

Dancer, C.E.J., Mikheenko, P., Bevan, A., Abel, J.S., Todd, R.I. and Grovenor, C.R.M. (2009). ‘A study of the sintering behaviour of Magnesium Diboride’, J. Eur. Ceram. Soc. 29(9) 1817-1824. 

Shapiro, I.P., Todd, R.I., Titchmarsh, J.M. and Roberts, S.G. (2009). ‘Effects of Y2O3 Additives and Powder Purity on the Densification and Grain Boundary Composition of Al2O3 / SiC Nanocomposites’, J. Eur. Ceram. Soc. 29(9) 1613-1624. 

Meng, F.C., Fu, Z.Y., Zhang, J.Y., Wang, H., Wang, W.M., Wang, Y.C., Todd, R.I. and Zhang, Q.J. (2008). ‘Study on the structure and properties of fine-grained alumina fast sintered with high heating rate’, MRS Bull. 43(12) 3521-3528. 

Chu, B.T.T., Tobias, G., Salzmann, C.G., Ballesteros, B., Grobert, N., Todd, R.I. and Green, M.L.H. (2008). ‘Fabrication of Carbon Nanotube Reinforced Glass-Ceramic Nanocomposites by Ultrasonic In-Situ Sol-Gel Processing’, J. Mater. Chem. 18(44) 5344 – 5349. 

Zhang, F.C., Luo, H.H., Wang, T.S., Roberts, S.G. and Todd, R.I. (2008). ‘Influence factors on wear resistance of two alumina matrix composites’, Wear 265(1-2) 27-33. 

Rust, M.A. and Todd, R.I. (2008). ‘High resolution surface studies of superplastic deformation in shear and tension’, Materialwissenschaft und Werkstofftechnik 39(4-5) 289-292.

Todd, R.I., Stowe, D., Galloway, S., Barnes, D. and Wilshaw, P.R. (2008). ‘Piezospectroscopic measurement of the stress field around and indentation crack tip in ruby using SEM cathodoluminescence’, J. Eur. Ceram. Soc. 28(10) 2049-2055.

Projects Available

Flash Sintering of Non-Oxide Ceramics for Armour
R I Todd, R Livesey (Dstl)

The most effective armour systems for military personnel rely on plates of non-oxide ceramics such as SiC to defeat incoming projectiles. These ceramics are expensive and difficult to produce because temperatures of ~2000 C, often with the simultaneous application of pressure, are needed to densify them. We have recently shown, however, that SiC can be densified without pressure at furnace temperatures less than 1200 C in just a few seconds in a new process known as "flash sintering" in which an electric field is applied to the ceramic during sintering. The aim of this project is to understand the mechanisms responsible for these remarkable improvements and hence to establish the advantages in cost, ballistic performance and manufacturing versatility for armour manufacture. The research will involve ceramic processing, microstructural characterisation and mechanical and ballistic testing.

This is a 4-year EPSRC Industrial CASE Studentship in conjunction with Dstl. Part of the time will be spent at Dstl's facilities. The project is only open to UK nationals.

Candidates are recommended to apply as soon as possible as applications will be considered on an individual basis as and when they are received and this position will be filled as soon as possible, but the latest date for considering applications will be 28 July 2017.

Subject to contract this project will be supported by a 4-year Industrial CASE Studentship sponsored by Dstl and the EPSRC. This 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 and the stipend will be at least £16,296 per year].

Any questions concerning the project can be addressed to Professor Richard Todd (richard.todd@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: Richard Todd

Flash sintering of ceramics
R I Todd

Normally, it takes several hours at a temperature well in excess of 1000 C to sinter a ceramic. However, it has recently been discovered that this can be achieved in a few seconds with much lower furnace temperatures by applying an electric current to the specimen whilst it is heated. We have shown that the "flash event" originates in a thermal runaway effect and have recently suggested that the rapid sintering observed during this flash event is primarily a consequence of the extremely rapid heating produced. The project aims to investigate the reasons for this and to establish models which will enable the commercial exploitation of the phenomenon.

Also see homepages: Richard Todd

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