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Call for Proposals

Priority Programme “Compositionally Complex Alloys – High Entropy Alloys (CCA-HEA)” (SPP 2006)

The Senate of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) established the Priority Programme “Compositionally Complex Alloys – High Entropy Alloys (CCA-HEA)” (SPP 2006). The programme is designed to run for six years. The present call invites proposals for the second three-year funding period.

Recently, a novel class of metallic alloys, referred to as “high entropy alloys” (HEA) or “compositionally complex alloys” (CCA), has been introduced. These alloys consist of near-equiatomic concentrations of multiple metallic elements. As such, they fundamentally differ from conventional alloys, which commonly consist of a primary element with additions of secondary (alloying) elements in order to achieve desired properties. This new concept of alloy design with no base element opens up a huge multi-component space with significant technological potential and poses challenging scientific questions.

The aim of this Priority Programme is to develop CCA and HEA with outstanding mechanical properties or displaying unusual phenomena, which cannot be obtained in conventional alloys, or be explained by current textbook-level theory. Within this programme, alloys with five or more elements are targeted, each having a concentration between 5 and 35 at. percent. Lower-order subsets of these alloys, namely binaries, ternaries and quaternaries, may be investigated in supporting roles only, in order to gain basic understanding of CCA and HEA. In order to optimise targeted materials properties, small additions of minor alloying elements such as C, B, Hf, Zr, Si, etc., are permitted.

The Priority Programme will comprise two branches:

  • high entropy alloys, HEA, which are defined within this Priority Programme as single solid solution phases, preferably with simple crystal structures
  • compositionally complex alloys, CCA, consisting of multiphase microstructures with two or more phases, which may include a solid solution phase

The HEA branch aims at the achievement of a basic-scientific understanding of materials properties that are due to the high entropy effect:

  • identification of specific properties that occur because of the salient features of HEA
  • repudiation of interpretations mistakenly ascribing properties as being specific to HEA
  • fundamental understanding of the characteristic structural and microstructural features of HEA, with particular attention to their influence on mechanical properties

The CCA branch will follow a more application-oriented approach. The aim is to identify and to tailor chemical, crystallographic or microstructural features that govern promising mechanical properties of CCA, making them attractive for future application. Alloys considered should have additional characteristics such as:

  • adequate room-temperature properties (including tensile ductility and fracture toughness)
  • ability to be produced in sufficiently large quantities (> 100 g and > 100 mm in size), which allow for conclusive determination of materials properties
  • machinability, so that desired specimen geometries can be prepared

In the CCA branch, special emphasis shall be placed on thorough characterisation of mechanical properties of the alloys, resulting in the need to include tensile testing. However, in order to support the application-oriented approach, hardness and compression testing may be used for initial fast screening, but should not be the main focus of a project. In addition to basic mechanical properties, the projects should focus on one or more of these areas:

  • mechanical behaviour at low, RT and elevated temperatures
  • fatigue
  • corrosion and oxidation resistance
  • aspects concerning diffusion effects
  • pointing out a connection between HEA- and CCA-properties, e.g. an optimised HEA acts as matrix for a CCA

In general: A working hypothesis that is in line with the overall scientific aims of the Priority Programme should be clearly presented in each of the proposals. Projects that include the development of production routes new for CCA or HEA should pay careful attention to microstructural stability within the range of desired application temperatures.

Due to the central importance of microstructure and some misleading statements in literature, in both the CCA and the HEA branches, special care has to be taken to thoroughly analyse the chemical and structural nature of the phases present in the specimens and to accurately document the specimens’ history (e.g. processing and heat treatment conditions).

Synergistic aspects: To maximise the scientific outcome of the Priority Programme, networking is essential to promote knowledge exchange between the different projects. Applicants are also highly encouraged to feedback knowledge obtained from research on HEA into research on CCA and vice versa, thereby increasing the chances of success in the identification and realisation of attractive materials properties. Collaborative research in joint projects is encouraged, including projects coupling simulations with experiments. While individual applicants are also eligible, great care should be taken to avoid a narrow focus of the project (e.g. microstructural characterisation divorced from any connection to relevant properties).

Restrictions: Projects primarily focusing on functional materials properties (e.g. magnetic or electronic properties, super-conductivity) will not be supported in the Priority Programme. Other important structural and physical materials properties, such as lattice parameters, thermal expansion, thermal and heat conductivity, may be studied. However, if these materials parameters behave in a regular way, they cannot be the main focus of a project. Projects applying established production routes or other techniques just for their own sake and without addressing a specific issue of CCA and HEA are not within the focus of this Priority Programme. Projects that are primarily theoretical in nature and do not include a significant experimental component, will not be supported.

Microstructures that are in a highly non-equilibrium state, e.g. metallic glasses, will not be considered. Only crystalline material will be considered in this Priority Programme. In certain cases, production routes with high cooling rates may be necessary. However, additional measures (e.g. heat treatment) need to be carried out in order to achieve a state close to equilibrium in the desired temperature range.

Proposals must be written in English and submitted to the DFG by 1 April 2020. Please note that proposals can only be submitted via elan, the DFG’s electronic proposal processing system.

Applicants must be registered in elan prior to submitting a proposal to the DFG. If you have not yet registered, please note that you must do so by 18 March 2020 to submit a proposal under this call; registration requests received after this time cannot be considered. You will normally receive confirmation of your registration by the next working day. Note that you will be asked to select the appropriate Priority Programme call during both the registration and the proposal process.

If you would like to submit a proposal for a new project within the existing Priority Programme, please go to Proposal Submission – New Project – Priority Programmes and select “SPP 2006” from the current list of calls. Previous applicants can submit a proposal for the renewal of an existing project under Proposal Submission – Proposal Overview/Renewal Proposal. Proposals by one applicant must not exceed 20 pages. Joint proposals may comprise five additional pages for each additional applicant.

In preparing your proposal, please review the programme guidelines (form 50.05, section B) and follow the proposal preparation instructions (form 54.01). These forms can either be downloaded from our website or accessed through the elan portal.

The review colloquium for the Priority Programme will be held on 17 June 2020 in Bayreuth.

Further Information
More information on the Priority Programme is available under:
www.sppccahea.uni-bayreuth.de

The elan system can be accessed at:
https://elan.dfg.de/en

DFG forms 50.05 and 54.01 can be downloaded at:
www.dfg.de/formulare/50_05
www.dfg.de/formulare/54_01

For scientific enquiries please contact the Priority Programme coordinator:
Prof. Dr.-Ing. Uwe Glatzel, Universität Bayreuth, Fakultät für Ingenieurwissenschaften, Lehrstuhl Metallische Werkstoffe, Prof.-Rüdiger-Bormann-Str. 1, 95447 Bayreuth, phone +49 921 55-6600, uwe.glatzel@uni-bayreuth.de

Questions on the DFG proposal process can be directed to:
Programme contact: Dr.-Ing. Xenia Molodova, phone +49 228 885-2374, xenia.molodova@dfg.de
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Administrative contact: Sergej Wachtel, phone +49 228 885-2241, sergej.wachtel@dfg.de