@misc{HanXuWangetal., author = {Han, Liuliu and Xu, Xiandong and Wang, Li and Pyczak, Florian and Zhou, Rui and Liu, Yong}, title = {A eutectic high-entropy alloy with good high-temperature strength-plasticity balance}, series = {Materials Research Letters}, volume = {7}, journal = {Materials Research Letters}, number = {11}, issn = {2166-3831}, pages = {460 -- 466}, language = {en} } @misc{LemosFredelPyczaketal., author = {Lemos, Georges and Fredel, M{\´a}rcio C. and Pyczak, Florian and Tetzlaff, Ulrich}, title = {Influence of distinct manufacturing processes on the microstructure of ni-based metal matrix composites submitted to long thermal exposure}, series = {Key Engineering Materials}, volume = {809}, journal = {Key Engineering Materials}, issn = {1662-9795}, doi = {10.4028/www.scientific.net/KEM.809.79}, pages = {79 -- 86}, language = {en} } @misc{WangOehringLiuetal., author = {Wang, Li and Oehring, Michael and Liu, Yuzhi and Lorenz, Uwe and Pyczak, Florian}, title = {Site occupancy of alloying elements in the L12 structure determined by channeling enhanced microanalysis in γ/γ' Co-9Al-9W-2X alloys}, series = {Acta Materialia}, volume = {162}, journal = {Acta Materialia}, isbn = {1359-6454}, pages = {176 -- 188}, 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{HauschildtStarkSchelletal., author = {Hauschildt, Katja and Stark, Andreas and Schell, Norbert and M{\"u}ller, Martin and Pyczak, Florian}, title = {The transient liquid phase bonding process of a γ-TiAl alloy with brazing solders containing Fe or Ni}, series = {Intermetallics}, volume = {106}, journal = {Intermetallics}, issn = {0966-9795}, pages = {48 -- 58}, language = {en} } @misc{SchnabelBargmannPauletal., author = {Schnabel, Jan Eike and Bargmann, Swantje and Paul, Jonathan David Heaton and Oehring, Michael and Pyczak, Florian}, title = {Work hardening and recovery in fully lamellar TiAl: relative activity of deformation systems}, series = {Philosophical Magazine}, volume = {99}, journal = {Philosophical Magazine}, number = {2}, issn = {1478-6435}, pages = {148 -- 180}, language = {en} } @misc{WangOehringLietal., author = {Wang, Li and Oehring, Michael and Li, Yuzhi and Song, Lin and Liu, Yon and Stark, Andreas and Lorenz, Uwe and Pyczak, Florian}, title = {Microstructure, phase stability and element partitioning of γ/γʹ Co-9Al-9W-2X alloys in different annealing conditions}, series = {Journal of Alloys and Compounds}, volume = {787}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, pages = {594 -- 605}, language = {en} } @misc{LiPyczakStarketal., author = {Li, Yuzhi and Pyczak, Florian and Stark, Andreas and Wang, Li and Oehring, Michael and Paul, Jonathan and Lorenz, Uwe}, title = {Temperature dependence of misfit in different Co-Al-W ternary alloys measured by synchrotron X-ray diffraction}, series = {Journal of Alloys and Compounds}, volume = {819}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, pages = {9}, language = {en} } @misc{SongWangZhangetal., author = {Song, Lin and Wang, Li and Zhang, Tiebang and Lin, Junpin and Pyczak, Florian}, title = {Microstructure and phase transformations of omega_o-Ti4Al3Nb based alloys after quenching and subsequent aging at intermediate temperatures}, series = {Journal of Alloys and Compounds}, volume = {821}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, pages = {11}, language = {en} } @misc{SongAppelWangetal., author = {Song, Lin and Appel, Fritz and Wang, Li and Oehring, Michael and Hu, Xingguo and Stark, Andreas and He, Junyang and Lorenz, Uwe and Zhang, Tiebang and Lin, Junpin and Pyczak, Florian}, title = {New insights into high-temperature deformation and phase transformation mechanisms of lamellar structures in high Nb-containing TiAl alloys}, series = {Acta Materialia}, volume = {186}, journal = {Acta Materialia}, issn = {1873-2453}, doi = {10.1016/j.actamat.2020.01.021}, pages = {575 -- 586}, language = {en} } @misc{LazurenkoLaptevGolkovskyetal., author = {Lazurenko, Daria V. and Laptev, Ilia S. and Golkovsky, Mikhail G. and Stark, Andreas and Paul, Jonathan and Bataev, Ivan A. and Ruktuev, Alexey A. and Song, Lin and Gollwitzer, Christian and Pyczak, Florian}, title = {Influence of the Ti/Al/Nb ratio on the structure and properties on intermetallic layers obtained on titanium by non-vacuum electron beam cladding}, series = {Materials Characterization}, volume = {163}, journal = {Materials Characterization}, issn = {1044-5803}, pages = {13}, language = {en} } @misc{XuPyczakYanetal., author = {Xu, Peng and Pyczak, Florian and Yan, Ma and Limberg, Wolfgang and Willumeit-R{\"o}mer, Regine and Ebel, Thomas}, title = {Tensile toughening of powder-injection-molded β Ti-Nb-Zr biomaterials by adjusting TiC particle distribution from aligned to dispersed pattern}, series = {Applied Materials Today}, volume = {19}, journal = {Applied Materials Today}, issn = {2352-9407}, doi = {10.1016/j.apmt.2020.100630}, pages = {14}, language = {en} } @misc{XuPyczakYangetal., author = {Xu, Peng and Pyczak, Florian and Yang, Ma and Kong, Fantao and Ebel, Thomas}, title = {Impacts of yttrium on microstructure and tensile properties of biomedical β Ti-Nb-Zr fabricated by metal injection molding}, series = {Materials Science and Engineering: A}, volume = {792}, journal = {Materials Science and Engineering: A}, issn = {0921-5093}, pages = {9}, 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{SoyamaLimbergEbeletal., author = {Soyama, Juliano and Limberg, Wolfgang and Ebel, Thomas and Pyczak, Florian}, title = {Sintering and Creep Resistance of Powder-Metallurgy-Processed Ti-(43-47)Al-5Nb-0.2B-0.2C}, series = {Advanced Engineering Materials}, volume = {22}, journal = {Advanced Engineering Materials}, number = {8}, issn = {1527-2648}, pages = {7}, language = {en} } @misc{IvanovLazurenkoStarketal., author = {Ivanov, Ivan V. and Lazurenko, Daria V. and Stark, Andreas and Pyczak, Florian and Th{\"o}mmes, Alexander and Bataev, Ivan A.}, title = {Application of Different Diffraction Peak Profile Analysis Methods to Study the Structure Evolution of Cold-Rolled Hexagonal α-Titanium}, series = {Metals and Materials International}, volume = {26}, journal = {Metals and Materials International}, number = {1}, issn = {2005-4149}, doi = {10.1007/s12540-019-00309-z}, pages = {83 -- 93}, language = {en} } @misc{JinHejaziPyczaketal., author = {Jin, Bowen and Hejazi, Seyedsina and Pyczak, Florian and Oehring, Michael and Mohajernia, Shiva and Kment, Stepan and Tomanec, Ondrej and Zboril, Radek and Nguyen, Nhat Truong and Yang, Min and Schmuki, Patrik}, title = {Amorphous Mo-Ta Oxide Nanotubes for Long-Term Stable Mo Oxide-Based Supercapacitors}, series = {ACS Applied Materials and Interfaces}, volume = {11}, journal = {ACS Applied Materials and Interfaces}, number = {49}, issn = {1944-8244}, pages = {45665 -- 45673}, language = {en} } @misc{LiuSongStarketal., author = {Liu, Xu and Song, Lin and Stark, Andreas and Lorenz, Uwe and He, Zhanbing and Lin, Junpin and Pyczak, Florian and Zhang, Tiebang}, title = {Deformation and phase transformation behaviors of a high Nb-containing TiAl alloy compressed at intermediate temperatures}, series = {Journal of Materials Science and Technology}, volume = {102}, journal = {Journal of Materials Science and Technology}, issn = {0861-9786}, doi = {10.1016/j.jmst.2021.06.041}, pages = {89 -- 96}, abstract = {In modern β-solidified TiAl alloys, the decomposition of α2 phase is frequently observed during heat treatment or high-temperature deformation of the alloys. In this study, high-temperature deformation and decomposition mechanisms of α2 phase in a Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y alloy are investigated. In a sample deformed at 800 °C, the precipitation of βo(ωo) phase is observed within the equiaxed α2 phase. The nucleation of ωo particles within the βo matrix indicates the α2→βo→ωo transformation. In addition, numerous γ phase precipitates form within the βo(ω) areas. The α2 lamellae decompose into ultrafine (α2+γ) lamellae and coarsened γ lamellae via α2→α2+γ and α2→γ transformation, respectively. Moreover, the ωo phase nucleates within the ultrafine lamellae via α2→ωo transformation. However, in a sample deformed at 1000 °C, the nucleation of βo particles is sluggish, which is caused by the efficient release of the internal stress via dynamic recrystallization (DRX). These results indicate that complex phase transformations can be introduced by the decomposition of α2 phase in TiAl alloys with a high amount of β-stabilizing elements.}, 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{DistlHauschildtRashkovaetal., author = {Distl, Benedikt and Hauschildt, Katja and Rashkova, Boryana and Pyczak, Florian and Stein, Frank}, title = {Phase Equilibria in the Ti-Rich Part of the Ti-Al-Nb System—Part I: Low-Temperature Phase Equilibria Between 700 and 900 °C}, series = {Journal of Phase Equilibria and Diffusion}, volume = {43}, journal = {Journal of Phase Equilibria and Diffusion}, number = {3}, issn = {1863-7345}, doi = {10.1007/s11669-022-00963-8}, pages = {355 -- 381}, abstract = {Precise knowledge of the phase equilibria in the Ti-Al-Nb system between 700 and 900 °C is of crucial importance for the urgently needed improvement of TiAl-based turbine materials already in industrial use to achieve further energy savings. As a result of the occurrence of the two ternary intermetallic phases ωo ("Ti4NbAl3") and O ("Ti2NbAl"), which form in the solid state just in the range of the application-relevant temperatures, the phase relations are very complex and not well studied. In the present investigation, isothermal sections of the Ti-rich part of the Ti-Al-Nb system at 700, 800, and 900 °C were determined by a systematic study of 15 ternary alloys, one solid-solid diffusion couple, and three liquid-solid diffusion couples. Using scanning electron microscopy, electron probe microanalysis (EPMA), x-ray diffraction (XRD), high-energy XRD (HEXRD), differential thermal analysis (DTA), and transmission electron microscopy (TEM) investigations, type and composition of phases as well as phase transitions were determined. With these results, the phase equilibria were established. A focus of the investigations is on the homogeneity ranges of the two ternary phases ωo and O, which both are stable up to temperatures above 900 °C. Based on the compositions measured for the ωo phase and its crystal structure type, a new formula (Ti,Nb)2Al is suggested. The results also indicate that the phase field of the ωo phase is split into two parts at 900 °C because of the growing phase field of the ordered (βTi,Nb)o phase.}, language = {en} } @misc{WangKongOehringetal., author = {Wang, Li and Kong, Yi and Oehring, Michael and Song, Min and Pyczak, Florian}, title = {Atomic site occupancy of alloying elements and Laves phase stability in γ-γ′ Co-base superalloys}, series = {Journal of Alloys and Compounds}, volume = {906}, journal = {Journal of Alloys and Compounds}, issn = {1873-4669}, doi = {10.1016/j.jallcom.2022.164261}, abstract = {The atomic site occupancy of alloying elements in the ZrCo2 and HfCo2 based Laves phases formed in the Co-9Al-9W-2Zr and Co-9Al-9W-2Hf alloys was experimentally determined by the combined techniques of energy-dispersive X-ray spectroscopy mapping with atomic resolution and the atom location by channeling enhanced microanalysis (ALCHEMI) method. The results show that both Al and W occupy the Zr site in the C15 and the Hf site in the C36 crystal structure. The atomic locations of Al and W were further confirmed by comparing calculated inelastic cross-sections with experimental ALCHEMI results. Using the determined atomic site occupancies of alloying elements, special quasirandom structure solid solution models with 192 atoms were constructed and employed in first-principles calculations. It is found theoretically that the energy of formation of the C15 structure is always lower than that of the C36 structure at 0 K in both ZrCo2 and HfCo2 phases, no matter whether Al and W are incorporated or not. However, further ab initio molecular dynamics simulations suggest that lattice vibration at finite temperature contributes significantly to the phase stability, stabilizing the C36 structure compared to the C15 type for the (Hf, Al, W)Co2 phase at finite temperature, which fits well with the experimental findings.}, language = {en} }