Research Projects

The atomic arrangements in extended planar defects in different types of Laves phases is studied by high-resolution scanning transmission electron microscopy. To understand the role of such defect phases for hydrogen storage, their interaction with hydrogen will be investigated. more

Adding 30 to 50 at.% aluminum to iron results in single-phase alloys with an ordered bcc-based crystal structure, so-called B2-ordered FeAl. Within the extended composition range of this intermetallic phase, the mechanical behavior varies in a very particular way. more

The precipitation of intermetallic phases from a supersaturated Co(Nb) solid solution is studied in a cooperation with the Hokkaido University of Science, Sapporo. more

The effect of Mo additions on the stability and crystal structure of the high-temperature phase Fe₅Al₈ (frequently called e phase) is investigated in a cooperation with the Los Alamos Neutron Science Center LANSCE. more

Within the EU project „ADVANCE - Sophisticated experiments and optimisation to advance an existing CALPHAD database for next generation TiAl alloys”, MPIE collaborated with Thermocalc-Software AB, Stockholm, Montanuniversität Leoben and Helmholtz-Zentrum Hereon, Geesthacht. At MPIE the focus lay on the production and heat treatments of model alloys and their analysis through metallography, X-ray diffraction, electron probe microanalysis and differential thermal analysis. Colleagues in Leoben performed transmission electron microscopy and at Helmholtz-Zentrum Hereon in situ synchrotron X-ray diffraction was carried out. All obtained data were optimised at the company Thermocalc and checked for consistency before they were implemented into the database. more

This project aims at getting a deeper understanding of  dendrite-like precipitates formed by a solid state decomposition of the high-temperature phase. To investigate this phenomena systematic variation of cooling rates and annealing times and temperatures for different alloy compositions are carried out.

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Because of their excellent corrosion resistance, high wear resistance and comparable low density, Fe–Al-based alloys are an interesting alternative for replacing stainless steels and possibly even Ni-base superalloys. Recent progress in increasing strength at high temperatures has evoked interest by industries to evaluate possibilities to employ Fe–Al-based alloys for various applications. These activities have matured to a point that industrial processing of parts is now investigated in more detail by considering economic aspects. more

Peritectoid transformations are a comparatively rare type of invariant reaction where in the solid state of a material, a phase A decomposes on heating into a mixture of two other phases B and C more

By combining advanced characterization and mechanical testing of microsized, single-phase intermetallic samples through in situ micromechanical experiments inside an SEM or TEM, the mechanical response can be measured while simultaneously observing the microstructural changes. From these experiments, it is expected to get a much deeper insight in the complicated deformation mechanism of intermetallic phases, which is very much different from that in pure metals. more

The Ni- and Co-based γ/γ’ superalloys are famous for their excellent high-temperature mechanical properties that result from their fine-scaled coherent microstructure of L1₂-ordered precipitates (γ’ phase) in an fcc solid solution matrix (γ phase). The only binary Co-based system showing this special type of microstructure is the Co-Ti system, where the Co solid solution is the γ phase and TiCo₃ the L1₂-ordered γ’ phase. more

Deviations from the ideal, stoichiometric composition of tcp (tetrahedrally close-packed) intermetallic phases as, e.g., Laves phases can be partially compensated by point defects like antisite atoms or vacancies, but also planar defects may offer an opportunity to accommodate excess atoms. more

TiAl-based alloys currently mature into application. Sufficient strength at high temperatures and ductility at ambient temperatures are crucial issues for these novel light-weight materials. By generation of two-phase lamellar TiAl + Ti₃Al microstructures, these issues can be successfully solved. Because oxidation resistance at high temperatures is still a problem which could be improved by increasing the Al content, Al-rich TiAl alloys have recently come into focus. more

Nb-based intermetallic alloys consisting of Nb solid solution and high-melting, strengthening intermetallic phases are of considerable interest for structural applications at very high temperatures. more

The next generation of Advanced Ultra Supercritical Coal-fired power plants (A-USC) aim at operating temperatures of approx. 700 °C and pressures of approx. 320 bars. Under these conditions, conventional ferritic steels are no longer usable. more

Substitution of so-called strategic elements such as Co, Nb, Ta or W becomes increasingly important to avoid political and economic dependencies. A possible replacement for alloys containing large amounts of strategic elements such as Cr-Ni steels or Ni- and Co-based alloys are Fe-Al-based alloys. Parts constructed out of Fe-Al-based alloys can be operated under high loads at high temperatures in aggressive environments. more

The objective of this large-scale collaborative research project is the development of intermetallic materials for application in large diesel ship engines. more

Today there is an increasing economic and ecological need for the development of new structural materials for applications at high temperatures. Possible candidates for such materials are metallic alloys containing high-melting intermetallic phases which retain high strengths at high temperatures. more

Fe-Al alloys in the composition range up to 50 at.% Al with disordered A2 or ordered B2 or D0₃ crystal structure are intensively discussed in the literature as potential materials for structural applications at elevated and high temperatures especially due to their excellent corrosion resistance and low density compared to conventional steels. more