@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} } @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{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{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{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{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{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} } @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} }