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Information für die Wissenschaft Nr. 40 | 11. Juli 2013
Priority Programme “Strong Coupling of Thermo-chemical and Thermo-mechanical States in Applied Materials” (SPP 1713)

The Senate of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) has announced the establishment of a new Priority Programme entitled ”Strong Coupling of Thermo-chemical and Thermo-mechanical States in Applied Materials” (SPP 1713). The programme is designed to run for six years; the present call invites proposals for the first three-year funding period.

Many applied materials like metals and solid-state polymers consist of multiple phases. Their properties depend crucially on their internal phase-structure, i.e. the fraction and local distribution of the phases, their composition and their molecular configuration. Chemical aspects influence the mechanical properties while mechanical load couples back to chemistry. This strong interrelation is expressed in the thermodynamic functional of the material which is composed of a thermo-chemical or thermo-solutal part on the one hand and a temperature-dependent mechanical part on the other hand. The central goal of the Priority Programme is the thermodynamically consistent modelling and simulation of the mutual interaction between chemistry and mechanics in applied materials, assisted by experimental characterisation.

“Chemical” in the sense of the programme is related to the generalised chemical potential as the derivative of an appropriate thermodynamic functional with respect to individual degrees of freedom of the system. Gradients in the chemical potential govern transformations of the phase-state of matter. Therefore, the projects shall be related to thermo-chemistry, but not treat chemical reaction, characterised by charge transfer between reactants.

Metals and polymers, commonly viewed as dead bodies, show strong mechanical response on changes of their constitution. They expand or contract by the formation of new crystallographic phases or show a macroscopic response by the shearing of crystal lattices. In return, external load or external fields can prevent or enhance phase separation in both, metals and polymers. Most applied materials are stabilised far out of equilibrium by an internal balance of chemical and mechanical forces. Examples of such materials are high strength steels where the supersaturated crystal lattice locks plastic relaxation, Ni-base superalloys in which a two-phase structure is stabilised by mechanical interaction, or immiscible polymer blends that show enhanced stiffness and toughness due to a phase-separation between the components. All of these materials cannot be understood without considering the interplay between phase-structure and mechanics.

In the Priority Programme combining methods of computational thermodynamics and thermo-mechanics, developed for metals, with methods for history dependent phase-structures and their thermo-mechanical behaviour, developed for polymers, on a general theoretical basis will evolve the full power of predictive materials modelling. It will enable scientists to describe structure and property of materials dependent on the process history and external chemo-mechanical load in a comprehensive way within a unified framework. The development and the validation of new comprehensive models and methods can also be based on qualitative and quantitative insights from atomistic simulations and experimental investigations.

Individual goals of the Priority Programme are:

  • Identification of the coupling mechanisms between thermo-chemistry and thermo-mechanics and their modelling, e.g. in the context of continuum thermodynamics or first-principles simulations.

  • Physically-based understanding of phase-structures in materials by the interplay of thermo-chemistry and thermo-mechanics, their generation and degradation as the basis for the modelling approaches.

  • Development of physically-based materials models, numerical models in the framework of thermo-chemo-mechanics, and tools to cope with these phenomena.

  • Provide datasets and thermo-mechanical coupling coefficients from ab-initio simulations or experiments to complete theoretical models.

  • Provide experimental benchmarks of materials states which show a strong chemo-mechanical coupling for the verification of theoretical models.

In the Priority Programme “complex” and “applied” materials shall be investigated. “Complex” in this context means that the material consists of several constituents (phases) with clearly distinct properties. “Applied” in this context means that the material under investigation shall be a multi-component system to mimic materials for a special application, but not with full technical intricacy. This reduction shall allow detailed studies of individual phenomena for a fundamental understanding as addressed in this Priority Programme.

Projects to be funded must be focussed on the central goal of the Priority Programme. In the projects the structural and the thermodynamic states must be coupled in two directions:

  • On the one hand, the phase-structure of the material depends on the state or the history of external chemo-mechanical loads and external fields (e.g. electric, magnetic).

  • On the other hand, the response of the material to loads depends on the phase-structure.

Dissipative mechanisms shall control the evolution of the material.

Project examples are:

  • Coupled thermo-chemical effects in multiphase steels by diffusion processes, where thermo-mechanical load triggers phase transformations.

  • Thermoplastic semi-crystalline polymers where the process-induced microstructure determines the local and global mechanical behaviour.

  • Nickel-based superalloys where soft gamma-channels separate and protect hard and brittle gamma prime-precipitates.

  • Polymer blends and their specific morphology of different (polymer) phases.

  • Diffusion processes, intermetallic phases, and Kirkendall effect in special systems, e.g. Au-Al wire-bonding.

  • Thermoplastic elastomers and block-copolymers with local phases.

  • Precipitation-hardened aluminium alloys which attain their properties by “aging”.

  • Strain-induced crystallisation of natural rubber.

  • Degradation of polymers under environmental loads.

  • Degradation of joints between metals under thermo-mechanical and environmental loads.

  • Functional polymers with field-controllable shape and mechanical properties.

Theoretically or numerically oriented projects are expected to identify and verify their models based on experimental data. The aim of the experimental investigations is to assist the development and validation of the theoretical or numerical work. Therefore the experimental part of individual projects must not exceed 50 percent of the total work.

Projects which primarily focus on production technology of the materials by melting and solidification or moulding and primary forming are excluded. However, solid-state production processes like metal forming may be considered to set the conditions for thermo-chemical load. Also, projects which primarily focus on fracture and failure, corrosion and surface technologies are excluded. Materials under investigation shall be metals and polymers. However, uniaxial long fibre-reinforced polymers and composites are excluded. Concrete, ceramics as the matrix material, wood, bone and other biological materials are also excluded.

The application of young scientists for independent projects is strongly encouraged. All applicants must include in their proposals a statement about the intended dissemination of project results and about their willingness to share data, models or software tools within the Priority Programme.

Proposals for the first three-year funding period can be submitted by 11 November 2013 through the DFG’s electronic proposal processing system “elan”. In the “elan” system please select “SPP 1713” when submitting your proposal. All proposals must be written in English. Proposal guidelines and preparation instructions are outlined in DFG forms 54.01en and 50.05en, part B. Proposals by one applicant must not exceed 20 pages. Joint proposals may comprise five additional pages for each additional applicant.

A colloquium and review panel meeting are planned for early 2014. The first funding period will start in mid-2014.

Further Information

The DFG’s electronic proposal processing system “elan” with proposal instructions and guidelines can be found at:

Proposal guidelines and preparation instructions are outlined in DFG forms 54.01en and 50.05en, part B, which can be found on the DFG’s website at:

For scientific enquiries concerning the scope of the programme, please contact the Priority Programme’s coordinator:

  • Professor Dr. Ingo Steinbach,
    Scale Bridging Thermodynamic and Kinetic Simulation,
    Interdisciplinary Centre for Advanced Materials Simulation (ICAMS),
    Ruhr-University Bochum,
    Universitätsstraße 90a,
    44789 Bochum,
    phone: +49 234 3229315,
    ingo.steinbach@rub.de

For administrative enquiries please contact:

  • Dr.-Ing. Burkhard Jahnen,
    Deutsche Forschungsgemeinschaft,
    53170 Bonn,
    phone: +49 228 885-2487,
    burkhard.jahnen@dfg.de

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