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Ralf Drautz

Professor Ralf Drautz
Visiting Professor

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

Tel: +44 1865 273777 (reception)
Fax: +44 1865 273789 (general fax)

ICAMS Homepage
Materials Modelling Laboratory

Summary of Interests

Theory of effective interatomic interactions. Application to understanding, predicting and designing properties of materials.

Current Research Projects

Simple models for the structural stability of TCP phases
B.J. Seiser, Dr. A.N. Kolmogorov, Dr. T. Hammerschmidt*, Professor R. Drautz*, Professor D.G. Pettifor
The precipitation of topologically close-packed (TCP) phases during the lifetime of a jet engine seriously degrades the mechanical properties of the nickel-based superalloy turbine blades. Atomistic simulations are being performed using a hierarchy of electronic structure models fromfirst principles density functional theory through the more chemically intuitive tight-binding model to analytic bond-order potential theory, in order to investigate the underlying origins of the structural trends between the A15, sigma, chi, mu and Laves TCP phases. Complementary to this theoretical investigation of binary phases, a novel two-dimensional structure map is also being developed that can handle the multi-component systems used in turbine blades. (In collaboration withthe University of Birmingham, Cambridge and Imperial College London.Funded by EPSRC.*ICAMS, Ruhr-Universität Bochum, Germany).

Atomistic modelling of the Fe-C system
M. Ford, Professor R. Drautz*, Professor D.G. Pettifor
Albeit Fe is one of the technologically most important elements, robust interatomic potentials for large scale atomistic simulations are not available.This is due to the magnetism of iron, its bcc phase is stabilized by the magnetic contribution to the energy over the hcp phase, which is the lowest energy phase if magnetism is not taken into account. In this project magnetic analytic bond-order potentials for iron will be developed and integrated with a potential for C. Thepotential will then be used for the calculation of the Fe-rich Fe-C phase diagram. (Funded by EPSRC(DTA).*ICAMS, Ruhr-Universität Bochum,Germany).

Atomistic modelling of Si-C coatings
P. Kamenski, Dr. A.N. Kolmogorov, Professor R. Drautz*, Professor D.G. Pettifor
Nanocomposite coatings are materials with unique properties that stemfrom a subtle interplay between the nanocrystalline grains and amorphous films, resulting in an overall hardness that exceeds the hardness of the individual components. In this project analytic bond-order potentialsare developed for modelling covalent SiC amorphous films. The robustnessof the interatomic potentials is validated by comparison to both experiment and first-principles density functional calculations. (Incollaboration with Fraunhofer IWM Freiburg and EMPA Dübendorf. Funded byNSF.*ICAMS, Ruhr-Universität Bochum, Germany).

Development of magnetic BOPs for Fe-Cr and Fe-Mn alloys
J. Drain, Professor R. Drautz, Professor D.G. Pettifor
Phase stability and defect behaviour in steels and iron-based alloys differs from non-ferrous materials as magnetism contributes to stabilize phases that otherwise would be unstable. Because magnetism has its origin in quantum mechanics, common classical interatomic potentials fail to describe the effect of magnetism on the formation of chemical bonds and therefore are unable to describe the phase stability ofsteels. Within this project, we will derive magnetic interatomic potentials that are suitable for large scale atomistic simulations of both ferritic and austenitic steels. The potentials will be applied to studying phase stability and the behaviour of extended defects in Fe-Crand Fe-Mn. (Funded by EPSRC(DTA).*ICAMS, Ruhr-Universität Bochum, Germany).

Atomistic modelling of Si-N coatings
J. Gehrmann, Dr. A.N. Kolmogorov, Professor R. Drautz*, Professor D.G. Pettifor
For the modelling of Si-N charge transfer has to be taken into account which requires an extension of the bond-based bond-order potentials for Si-C that are developed in the project "Atomistic modelling of Si-Ccoatings". In this project we include charge transfer into the bond-based BOP formalism. The potentials for Si-N and Si-C are then used in large-scale atomistic simulations of the growth of amorphous thin films. (In collaboration with Fraunhofer IWM Freiburg and EMPADübendorf. Funded by EPSRC.*ICAMS, Ruhr-Universität Bochum, Germany).

5 public active projects

Research Publications

Please see here for an up to date list of publications.