@misc{BauerNeumeierPyczaketal., author = {Bauer, A. and Neumeier, Steffen and Pyczak, Florian and Singer, Robert F. and G{\"o}ken, Mathias}, title = {Creep properties of different γ'- strengthened Co-base superalloys}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {550}, issn = {1873-4936}, pages = {333 -- 341}, language = {en} } @inproceedings{BauerNeumeierPyczaketal., author = {Bauer, Alexander and Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Creep strength and microstructure of polycrystalline γ'-strengthened cobalt-base superalloys}, series = {Superalloys 2012, proceedings of the 12th International Symposium on Superalloys, held September 9-13, 2012 at Seven Springs Mountain Resort, Seven Springs, PA}, booktitle = {Superalloys 2012, proceedings of the 12th International Symposium on Superalloys, held September 9-13, 2012 at Seven Springs Mountain Resort, Seven Springs, PA}, editor = {Huron, Eric S. and Reed, Roger C. and Hardy, Mark C. and Mills, Michael J. and Montero, Rick E. and Portella, Pedro D. and Telesmann, Jack}, publisher = {Wiley [u.a.]}, address = {Hoboken, New Jersey}, isbn = {978-1-118-51643-0}, pages = {695 -- 703}, language = {en} } @misc{SchlofferIqbalGabrischetal., author = {Schloffer, Martin and Iqbal, Farasat and Gabrisch, Heike and Schwaighofer, Emanuel and Schimansky, Frank-Peter and Mayer, Svea and Stark, Andreas and Lippmann, Thomas and G{\"o}ken, Mathias and Pyczak, Florian and Clemens, Helmut}, title = {Microstructure development and hardness of a powder metallurgical multi phase gamma-TiAl based alloy}, series = {Intermetallics}, journal = {Intermetallics}, number = {22}, issn = {0966-9795}, doi = {10.1016/j.intermet.2011.11.015}, pages = {231 -- 240}, language = {en} } @misc{NeumeierDinkelPyczaketal., author = {Neumeier, Steffen and Dinkel, Michael and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Nanoindentation and XRD investigations of single crystalline Ni-Ge brazed nickel-base superalloys PWA 1483 and Ren{\´e} N5}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {528}, issn = {1873-4936}, pages = {815 -- 822}, language = {en} } @misc{BauerNeumeierPyczaketal., author = {Bauer, A. and Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Microstructure and creep strength of different γ/γ'- strengthened Co-base superalloy variants}, series = {Scripta Materialia}, volume = {63}, journal = {Scripta Materialia}, number = {12}, issn = {1359-6462}, pages = {1197 -- 1200}, language = {en} } @misc{PyczakNeumeierGoeken, author = {Pyczak, Florian and Neumeier, Steffen and G{\"o}ken, Mathias}, title = {Temperature Dependence of Element Partitioning in Rhenium and Ruthenium Bearing Nickel-Base Superalloys}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {527}, issn = {1873-4936}, pages = {7939 -- 7943}, language = {en} } @misc{NeumeierPyczakGoeken, author = {Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Influence of Rhenium and Ruthenium on Local Mechanical Properties of Nickel-Base Superalloys}, series = {Philosophical Magazine A}, volume = {91}, journal = {Philosophical Magazine A}, number = {33}, issn = {1478-6443}, pages = {4187 -- 4199}, language = {en} } @misc{GebhardPyczakGoeken, author = {Gebhard, Susanne and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Microstructural and Micromechanical Characterisation of TiAl Alloys Using Atomic Force Microscopy and Nanoindentation}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {523}, issn = {1873-4936}, pages = {235 -- 241}, language = {en} } @misc{PyczakNeumeierGoeken, author = {Pyczak, Florian and Neumeier, Steffen and G{\"o}ken, Mathias}, title = {Change of Internal Stress and Strain States in Nickel-Base Superalloys during Creep Deformation}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {510-511}, issn = {1873-4936}, pages = {295 -- 300}, language = {en} } @misc{RettigHecklNeumeieretal., author = {Rettig, Ralf and Heckl, Astrid and Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias and Singer, Robert F.}, title = {Verification of a commercial CALPHAD database for Re and Ru containing nickel-base superalloys}, series = {Defect and Diffusion Forum}, journal = {Defect and Diffusion Forum}, number = {289-292}, issn = {1662-9507}, pages = {101 -- 108}, language = {en} } @misc{DinkelPyczakMayetal., author = {Dinkel, Michael and Pyczak, Florian and May, Johannes and H{\"o}ppel, Heinz Werner and G{\"o}ken, Mathias}, title = {XRD profile analysis characterization of ultrafine grained Al-Mg alloys}, series = {Journal of Materials Science}, volume = {43}, journal = {Journal of Materials Science}, number = {23-24}, issn = {1573-4803}, pages = {7481 -- 7487}, language = {en} } @inproceedings{HeinzVolekSingeretal., author = {Heinz, Paul and Volek, Andreas and Singer, Robert F. and Dinkel, Michael and Pyczak, Florian and G{\"o}ken, Mathias and Ott, Michael and Affeldt, Ernst and Vossberg, Andreas}, title = {Diffusion brazing of single crystalline nickel base superalloys using boron free nickel base braze alloys}, series = {Diffusion in Solids and Liquids III, 3rd International Conference on Diffusion in Solids and Liquids, Liege Konferenz}, booktitle = {Diffusion in Solids and Liquids III, 3rd International Conference on Diffusion in Solids and Liquids, Liege Konferenz}, editor = {{\"O}chsner, Andreas and Murch, Graeme E.}, publisher = {Trans Tech Publ.}, address = {Stafa-Zurich [u.a.]}, isbn = {978-3-908451-51-8}, pages = {294 -- 299}, language = {en} } @inproceedings{DurstPyczakBiermannetal., author = {Durst, K. and Pyczak, Florian and Biermann, H. and G{\"o}ken, Mathias and Mughrabi, Hael and Vehoff, H.}, title = {Microstructural and micromechanical characterisation of nickel-base superalloys by CBED and nanoindentation investigations}, series = {Proceedings, Materials Week 2002}, booktitle = {Proceedings, Materials Week 2002}, publisher = {Werkstoffinformationsgesellschaft mbH}, address = {Frankfurt am Main}, isbn = {3-88355-314-X}, language = {en} } @misc{BauerNeumeierPyczaketal., author = {Bauer, Alexander and Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Influence of Iridium on the Properties of γ′-Strengthened Co-Base Superalloys}, series = {Advanced Engineering Materials}, volume = {17}, journal = {Advanced Engineering Materials}, number = {6}, issn = {1527-2648}, pages = {748 -- 754}, language = {en} } @misc{WangZenkStarketal., author = {Wang, Li and Zenk, Carolin and Stark, Andreas and Felfer, Peter and Gabrisch, Heike and G{\"o}ken, Mathias and Lorenz, Uwe and Pyczak, Florian}, title = {Morphology evolution of Ti3AlC carbide precipitates in high Nb containing TiAl alloys}, series = {Acta Materialia}, journal = {Acta Materialia}, number = {137}, issn = {1359-6454}, pages = {36 -- 44}, language = {en} } @misc{KolbWheelerMathuretal., author = {Kolb, M. and Wheeler, Jeffrey M. and Mathur, H. N. and Neumeier, Steffen and Korte-Kerzel, Sandra and Pyczak, Florian and Michler, Johann and G{\"o}ken, Mathias}, title = {Local mechanical properties of the (β0+ω0) composite in multiphase titanium aluminides studied with nanoindentation at room and high temperatures}, series = {Materials Science and Engineering A}, volume = {665}, journal = {Materials Science and Engineering A}, issn = {0921-5093}, doi = {10.1016/j.msea.2016.04.026}, pages = {135 -- 140}, language = {en} } @misc{IqbalPyczakNeumeieretal., author = {Iqbal, Farasat and Pyczak, Florian and Neumeier, Steffen and G{\"o}ken, Mathias}, title = {Crack nucleation and elastic / plastic deformation of TiAl alloys investigated by in-situ loaded atomic force microscopy}, series = {Materials Science and Engineering : A, Structural materials}, volume = {689}, journal = {Materials Science and Engineering : A, Structural materials}, issn = {0921-5093}, pages = {11 -- 16}, language = {en} } @misc{PyczakBauerGoekenetal., author = {Pyczak, Florian and Bauer, Alexander and G{\"o}ken, Mathias and Lorenz, Uwe and Neumeier, Steffen and Oehring, Michael and Paul, Jonathan and Schell, Norbert and Schreyer, Andreas and Symanzik, Felix}, title = {The effect of tungsten content on the properties of L12-hardened Co-Al-W alloys}, series = {Journal of Alloys and Compounds}, journal = {Journal of Alloys and Compounds}, number = {632}, issn = {0925-8388}, pages = {110 -- 115}, language = {en} } @inproceedings{NeumeierPyczakGoeken, author = {Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {The Influence of Ruthenium and Rhenium on the local Properties of the gamma- and gamma'-Phase in Nickel-Base Superalloys and their Consequences for Alloy Behaviour}, series = {Superalloys 2008, proceedings of the Eleventh International Symposium on Superalloys, held September 14 - 18, 2008, Pennsylvania, USA}, booktitle = {Superalloys 2008, proceedings of the Eleventh International Symposium on Superalloys, held September 14 - 18, 2008, Pennsylvania, USA}, editor = {Reed, Roger C. and Green, Kenneth A. and Caron, Pierre and Gabb, Timothy P. and Fahrmann, Michael G. and Huron, Eric S. and Woodard, Shiela R.}, publisher = {TMS}, address = {Warrendale, Pa.}, isbn = {978-0-87339-728-5}, pages = {109 -- 119}, language = {en} } @inproceedings{DinkelPyczakGoekenetal., author = {Dinkel, Michael and Pyczak, Florian and G{\"o}ken, Mathias and Heinz, Paul and Volek, Andreas and Singer, Robert F. and Ott, Michael and Affeldt, Ernst and Vossberg, Andreas}, title = {Nanoindentation and Orientation Measurements in Single Crystalline Brazing Joints of Nickel-Base Superalloys}, series = {Materials for advanced power engineering 2006, proceedings of the 8th Liege Conference, Bd. 2}, booktitle = {Materials for advanced power engineering 2006, proceedings of the 8th Liege Conference, Bd. 2}, editor = {Lecomte-Beckers, Jacqueline and Carton, M. and Schubert, F. and Ennis, P. J.}, publisher = {Forschungszentrum}, address = {J{\"u}lich}, isbn = {3-89336-436-6}, pages = {633 -- 642}, language = {en} } @misc{LiangPaulStarketal., author = {Liang, Zhida and Paul, Jonathan and Stark, Andreas and Bezold, Andreas and Neumeier, Steffen and G{\"o}ken, Mathias and Pyczak, Florian}, title = {High-Temperature CoNi-Based Superalloys Strengthened by γ′-(Ni,Co)3(Cr,Al,Ti,X): The Effect of Refractory Elements}, series = {Metallurgical and materials transactions. A, Physical metallurgy and materials science}, volume = {54 (2023)}, journal = {Metallurgical and materials transactions. A, Physical metallurgy and materials science}, number = {5}, issn = {1543-1940}, doi = {10.1007/s11661-022-06795-y}, pages = {1620 -- 1634}, abstract = {Recent research on Co-based and CoNi-based alloys revealed that the Co-Al-W-system provides interesting properties, however, the high content of W addition triggers high mass density of alloys which limits its industrial application. Therefore, new high temperature superalloys based on the Co-Ni-Al-Ti-system with high content Cr and strengthened by γ′-(Ni,Co)3(Cr,Al,Ti) precipitates, have been developed, and the effect of different refractory element additions was investigated. STEM-EDS and HEXRD were employed to determine the elemental partitioning behavior and the lattice misfit between the γ and γ′ phases. Ta and Nb strongly concentrate within the γ′ phase, whereas Mo weakly partitions to the γ phase. W distributes equally between the γ and γ′ phases. These new superalloys have an unexpectedly high positive misfit compared with some conventional Ni-based superalloys and Co-based superalloys. Nb and Ta additions increase the lattice misfit further, while Mo and W decrease the lattice misfit. The effect of refractory elements alloying on the yield stress at room temperature was evaluated by analyzing the contributions of different strengthening mechanisms. Alloying with Nb or Ta significantly improves precipitation strengthening by increasing the antiphase boundary energy. Mo has the highest solid solution strengthening effect in the γ phase, followed by W. Compared with some conventional Ni-based superalloys, the investigated new CoNi-based superalloys exhibited better mechanical properties at high temperature, which indicates that these compositionally complex alloys are possible candidates for high temperature applications.}, language = {en} } @misc{LiangNeumeierRaoetal., author = {Liang, Zhida and Neumeier, Steffen and Rao, Ziyuan and G{\"o}ken, Mathias and Pyczak, Florian}, title = {CALPHAD informed design of multicomponent CoNiCr-based superalloys exhibiting large lattice misfit and high yield stress}, series = {Materials Science and Engineering: A, Structural materials}, volume = {854}, journal = {Materials Science and Engineering: A, Structural materials}, issn = {1873-4936}, doi = {10.1016/j.msea.2022.143798}, abstract = {Usually, Co-based superalloys contain a high fraction of W and/or Mo. The refractory elements stabilize the precipitate phase, but cause a high density. In this work, new L12-phase hardened, low-density CoNiCr-based superalloys were developed with the assistance of CALPHAD calculations. Several alloys were studied experimentally and their microstructures, elemental distributions, lattice parameters and the lattice misfit between the γ and γ′ phases were evaluated using scanning electron microscopy, transmission electron microscopy, atom probe tomography and high energy X-ray diffraction. The alloys exhibit a very high misfit, good phase stability and excellent mechanical strength. It was found by hardness tests that a two-step heat treatment improves the strength of the new alloys even further. In comparison with conventional Co-based superalloys, Co-Al-W based superalloys and Co-Ti based superalloys, as well as Ni-based superalloys, i.e. Udimet 720Li, they have a low mass density and high yield stress. They also overcome the problem of a generally low lattice misfit of previous L12-phase hardened CoNiCr-based superalloys with high Ni and Cr contents. As a result, they show cuboidal-shaped precipitates similar to Co-Al-W and Co-Al-Mo based superalloys.}, language = {en} } @misc{PyczakBauerGoekenetal., author = {Pyczak, Florian and Bauer, A. and G{\"o}ken, Mathias and Neumeier, Steffen and Lorenz, U. and Oehring, Michael and Schell, N. and Schreyer, Andreas and Stark, Andreas and Szymanzik, F.}, title = {Plastic Deformation Mechanisms in a Crept L12 hardened Co-Base Superalloy}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {571}, issn = {1873-4936}, pages = {13 -- 18}, language = {en} } @misc{NeumeierPyczakGoeken, author = {Neumeier, Steffen and Pyczak, Florian and G{\"o}ken, Mathias}, title = {The temperature dependent lattice misfit of rhenium and ruthenium containing nickel-base superalloys-experiment and modelling}, series = {Materials and Design}, volume = {198}, journal = {Materials and Design}, issn = {0264-1275}, pages = {14}, language = {en} } @misc{BreslerNeumeierZieneretal., author = {Bresler, Johannes and Neumeier, Steffen and Ziener, Marco and Pyczak, Florian and G{\"o}ken, Mathias}, title = {The influence of niobium, tantalum and zirconium on the microstructure and creep strength of fully lamellar γ/α2 titanium aluminides}, series = {Materials Science and Engineering}, volume = {744}, journal = {Materials Science and Engineering}, issn = {0921-5093}, doi = {10.1016/j.msea.2018.11.152}, pages = {46 -- 53}, language = {en} } @misc{FreundStarkPyczaketal., author = {Freund, Lisa P. and Stark, Andreas and Pyczak, Florian and Schell, Norbert and G{\"o}ken, Mathias and Neumeier, Steffen}, title = {The grain boundary pinning effect of the µ phase in an advanced polycrystalline γ/γʹ Co-base superalloy}, series = {Journal of Alloys and Compounds}, volume = {753}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2018.04.204}, pages = {333 -- 342}, language = {en} } @misc{FreundStarkKirchmayeretal., author = {Freund, Lisa P. and Stark, Andreas and Kirchmayer, Andreas and Schell, Norbert and Pyczak, Florian and G{\"o}ken, Mathias and Neumeier, Steffen}, title = {The Effect of a Grain Boundary Pinning B2 Phase on Polycrystalline Co-Based Superalloys with Reduced Density}, series = {Metallurgical and Materials Transactions A}, volume = {49}, journal = {Metallurgical and Materials Transactions A}, number = {9}, issn = {1543-1940}, doi = {10.1007/s11661-018-4757-2}, pages = {4070 -- 4078}, language = {en} } @misc{DinkelHeinzPyczaketal., author = {Dinkel, Michael and Heinz, Paul and Pyczak, Florian and Volek, Andreas and Ott, Michael and Affeldt, Ernst and Vossberg, Andreas and G{\"o}ken, Mathias and Singer, Robert F.}, title = {New Boron and Silicon Free Single Crystal-Diffusion Brazing Alloys}, series = {Superalloys 2008, proceedings of the Eleventh International Symposium on Superalloys, held September 14 - 18, 2008, Pennsylvania, USA}, journal = {Superalloys 2008, proceedings of the Eleventh International Symposium on Superalloys, held September 14 - 18, 2008, Pennsylvania, USA}, editor = {Reed, Roger C. and Green, Kenneth A. and Caron, Pierre and Gabb, Timothy P. and Fahrmann, Michael G. and Huron, Eric S. and Woodard, Shiela R.}, publisher = {TMS}, address = {Warrendale, Pa.}, isbn = {978-0-87339-728-5}, pages = {211 -- 220}, language = {en} } @misc{HaussmannNeumeierBresleretal., author = {Haußmann, Lukas and Neumeier, Steffen and Bresler, Johannes and Keim, Simon and Pyczak, Florian and G{\"o}ken, Mathias}, title = {Influence of Nb, Ta and Zr on the Interdiffusion Coefficients and Solid Solution Strengthening of γ-TiAl Single Phase Alloys}, series = {Metals}, volume = {12}, journal = {Metals}, number = {5}, issn = {2075-4701}, doi = {10.3390/met12050752}, abstract = {The alloying elements Nb, Ta and Zr improve the creep properties of fully lamellar γ/α2 titanium aluminides significantly. Since high temperature deformation mainly occurs in the γ-phase of γ/α2 titanium aluminides, the diffusivity and the solid solution hardening effect of these three elements in the γ-phase is studied by analyzing the concentration gradients of the alloying elements and the resulting hardness across the interdiffusion zone of diffusion couples by energy dispersive X-ray diffraction and nanoindentation. The results reveal that Zr has the highest interdiffusion coefficient but also the largest solid solution hardening coefficient. The mechanical properties of single γ-phase Ti-54Al-5X alloys were investigated by strain rate jump tests. The addition of 5 at.\% Nb or Ta lead to an increased strength compared to a binary γ-Ti-54Al alloy. The Zr-containing γ-TiAl alloy reveals the highest strength at 750°C and 900°C, which is discussed to be due to the strong solid solution hardening effect of Zr. However, in comparison to the other alloys, Ti-54Al-5Zr shows quite brittle behavior up to 900°C. The lower diffusivity of Ta compared to Nb leads to a higher strength of the Ta-modified alloy at 900◦C.}, language = {en} }