@inproceedings{GlavatskikhLindemannLeyensetal., author = {Glavatskikh, Maria and Lindemann, Janny and Leyens, Christoph and Oehring, Michael and Appel, Fritz}, title = {Surface Strengthening for Enhanced Fatigue Performance of Gamma Titanium Aluminides}, series = {Structural aluminides for elevated temperatures, proceedings of the Structural Aluminides for Elevated Temperatures Symposium, held during TMS 2008 annual meeting \& exhibition, New Orleans, Louisiana, USA, March 9 - 13, 2008}, booktitle = {Structural aluminides for elevated temperatures, proceedings of the Structural Aluminides for Elevated Temperatures Symposium, held during TMS 2008 annual meeting \& exhibition, New Orleans, Louisiana, USA, March 9 - 13, 2008}, editor = {Kim, Young-Won}, publisher = {TMS}, address = {Warrendale, Pa.}, isbn = {978-0-87339-720-9}, pages = {111 -- 118}, language = {en} } @incollection{LindemannGlavatskikhLeyensetal., author = {Lindemann, Janny and Glavatskikh, Maria and Leyens, Christoph and Oehring, Michael and Appel, Fritz}, title = {Influence of Mechanical Surface Treatments on the High Cycle Fatigue Performance of Gamma Titanium Aluminides}, language = {en} } @article{LindemannKutzscheOehringetal., author = {Lindemann, Janny and Kutzsche, Anja and Oehring, Michael and Appel, Fritz}, title = {Influence of Mechanical Surface Treatments on the Fatigue Performance of the Gamma TiAl Alloy Ti-45Al-9Nb-0.2C}, series = {Materials Science Forum}, volume = {539-543}, journal = {Materials Science Forum}, issn = {0255-5476}, pages = {1553 -- 1558}, language = {en} } @misc{OehringStarkPauletal., author = {Oehring, Michael and Stark, Andreas and Paul, Jonathan David Heaton and Lippmann, Thomas and Pyczak, Florian}, title = {Microstructural refinement of boron-containing β-solidifying γ-titanium aluminide alloys through heat treatments in the β phase field}, series = {Intermetallics}, journal = {Intermetallics}, number = {32}, isbn = {0966-9795}, pages = {12 -- 20}, language = {en} } @misc{LimbergEbelPyczaketal., author = {Limberg, Wolfgang and Ebel, Thomas and Pyczak, Florian and Oehring, Michael and Schimansky, Frank-Peter}, title = {Influence of the sintering atmosphere on the mechanical properties of MIM-processed Ti 45Al 5Nb 0.2B 0.2C}, series = {Materials Science and Engineering A}, journal = {Materials Science and Engineering A}, number = {552}, pages = {323 -- 329}, 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} } @inproceedings{GabrischLorenzOehringetal., author = {Gabrisch, Heike and Lorenz, Uwe and Oehring, Michael and Paul, Jonathan and Pyczak, Florian and Rackel, Marcus W. and Schimansky, Frank-Peter and Stark, Andreas}, title = {TiAlNb-alloy with a modulated B19 containing constituent produced by powder metallurgy}, series = {Intermetallic-based alloys - science, technology and applications, symposium held November 25-30, Boston, Massachusetts, U.S.A}, booktitle = {Intermetallic-based alloys - science, technology and applications, symposium held November 25-30, Boston, Massachusetts, U.S.A}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, doi = {10.1557/opl.2012.1575}, pages = {35 -- 40}, language = {en} } @misc{EbelFerriLimbergetal., author = {Ebel, Thomas and Ferri, Orley Milagres and Limberg, Wolfgang and Oehring, Michael and Pyczak, Florian and Schimansky, Frank-Peter}, title = {Metal injection moulding of titanium and titanium-aluminides}, series = {Key Engineering Materials}, journal = {Key Engineering Materials}, number = {520}, issn = {1662-9795}, pages = {153 -- 160}, language = {en} } @misc{StarkOehringPyczaketal., author = {Stark, Andreas and Oehring, Michael and Pyczak, Florian and Lippmann, Thomas and Lottermoser, Lars and Schreyer, Andreas}, title = {The transformation mechanism of β phase to ω-related phases in Nb-rich γ-TiAl alloys studied by in situ high-energy X-ray diffraction}, series = {Materials Science Forum}, journal = {Materials Science Forum}, number = {772}, issn = {1662-9752}, pages = {85 -- 89}, language = {en} } @misc{StaronBeckmannLippmannetal., author = {Staron, Peter and Beckmann, Felix and Lippmann, Thomas and Stark, Andreas and Oehring, Michael and Pyczak, Florian and Salgado, Mario and Hort, Norbert and Eckerlebe, Horst and Kainer, Karl Ulrich and M{\"u}ller, Martin and Schreyer, Andreas}, title = {In situ studies of light metals with synchrotron radiation and neutrons}, series = {Materials Science Forum}, journal = {Materials Science Forum}, number = {690}, issn = {1662-9752}, pages = {192 -- 197}, language = {en} } @inproceedings{StarkOehringPyczak, author = {Stark, Andreas and Oehring, Michael and Pyczak, Florian}, title = {Influence of Quenching Rates on the Transformation of Ternary Phases in Nb-rich γ-TiAl Alloys}, series = {Intermetallic-based alloys for structural and functional applications, symposium held November 29 - December 3, Boston, Massachusetts, U.S.A}, booktitle = {Intermetallic-based alloys for structural and functional applications, symposium held November 29 - December 3, Boston, Massachusetts, U.S.A}, editor = {Palm, Martin and Bewlay, Bernard P. and Kumar, K. Sharvan and Yoshimi, Kyosuke}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, doi = {doi:10.1557/opl.2011.30}, pages = {107 -- 112}, language = {en} } @misc{PyczakAppelLimbergetal., author = {Pyczak, Florian and Appel, Fritz and Limberg, Wolfgang and Lorenz, Uwe and Oehring, Michael and Paul, Jonathan and Schimansky, Frank-Peter}, title = {Novel Processing Techniques for gamma-TiAl Alloys}, series = {Materials Science Forum}, journal = {Materials Science Forum}, number = {690}, issn = {1662-9752}, pages = {145 -- 148}, language = {en} } @misc{StarkOehringPyczaketal., author = {Stark, Andreas and Oehring, Michael and Pyczak, Florian and Schreyer, Andreas}, title = {In Situ Observation of Various Phase Transformation Paths in Nb-Rich TiAl Alloys during Quenching with Different Rates}, series = {Advanced Engineering Materials}, volume = {18}, journal = {Advanced Engineering Materials}, number = {8}, issn = {1527-2648}, pages = {700 -- 704}, language = {en} } @misc{BolzOehringLindemannetal., author = {Bolz, Sebastian and Oehring, Michael and Lindemann, Janny and Pyczak, Florian and Paul, Jonathan and Stark, Andreas and Lippmann, Thomas and Roth-Fagaraseanu, Dan and Schreyer, Andreas and Weiß, Sabine and Schr{\"u}fer, Susanne}, title = {Microstructure and mechanical properties of a forged beta-solidifying gamma TiAl alloy in different heat treatment conditions}, series = {Intermetallics}, volume = {2015}, journal = {Intermetallics}, number = {58}, pages = {71 -- 83}, 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} } @misc{OehringLindemannPyczaketal., author = {Oehring, Michael and Lindemann, Janny and Pyczak, Florian and Paul, Jonathan and Stark, Andreas and Lippmann, Thomas and Schr{\"u}fer, Susanne and Roth-Fagaraseanu, Dan and Schreyer, Andreas and Weiß, Sabine}, title = {Microstructure and mechanical properties of a forged β-solidifying γ TiAl alloy in different heat treatment conditions}, series = {Intermetallics}, volume = {2015}, journal = {Intermetallics}, number = {58}, issn = {0966-9795}, doi = {10.1016/j.intermet.2014.11.008}, pages = {71 -- 83}, abstract = {In the cast condition g titanium aluminide alloys that solidify completely through the b phase are characterized by fine and homogeneous microstructures, weak textures and low segregation. For these reasons such alloys have a relatively good workability and can be closed-die forged without preceding ingot breakdown even if the alloys contain no large fractions of the b phase at the working temperature. The present work was devoted to a combined study of the constitution and microstructural morphologies that develop in various two-step heat treatments of a single-step forged b solidifying alloy. The study included high-energy X-ray diffraction for in situ investigations of the constitution at the heat treatment temperature. It was observed that the phase ransformations are quite sluggish in the material which results in fine microstructures and some conditions that significantly deviate from thermodynamic equilibrium. Further, tensile and creep testing was carried out on the different material conditions in order to identify the range in which the properties can be varied. It is found that this easily forgeable material exhibits comparable strength, ductility and creep strength as more conventional peritectically solidifying alloys.}, language = {en} } @misc{SoyamaOehringLimbergetal., author = {Soyama, Juliano and Oehring, Michael and Limberg, Wolfgang and Ebel, Thomas and Kainer, Karl Ulrich and Pyczak, Florian}, title = {The effect of zirconium addition on sintering behaviour, microstructure and creep resistance of the powder metallurgy processed alloy Ti-45Al-5Nb-0.2B-0.2C}, series = {Materials and Design}, volume = {84}, journal = {Materials and Design}, issn = {0261-3069}, pages = {87 -- 94}, language = {en} } @misc{SoyamaOehringLimbergetal., author = {Soyama, Juliano and Oehring, Michael and Limberg, Wolfgang and Ebel, Thomas and Kainer, Karl Ulrich and Pyczak, Florian}, title = {Sintering behaviour of Ti-45Al-5Nb-0.2B-0.2C alloy modifications by additions of elemental titanium and aluminium}, series = {Powder Metallurgy}, volume = {58}, journal = {Powder Metallurgy}, number = {5}, issn = {1743-2901}, pages = {369 -- 375}, language = {en} } @misc{StarkRackelTchouahaTankouaetal., author = {Stark, Andreas and Rackel, Marcus W. and Tchouaha Tankoua, Aristide and Oehring, Michael and Schell, Norbert and Lottermoser, Lars and Schreyer, Andreas and Pyczak, Florian}, title = {In situ High-Energy X-Ray Diffraction during Hot-Forming of a Multiphase TiAl Alloy}, series = {Metals}, volume = {5}, journal = {Metals}, number = {4}, issn = {2075-4701}, pages = {2252 -- 2265}, language = {en} } @misc{LiPyczakOehringetal., author = {Li, Yuzhi and Pyczak, Florian and Oehring, Michael and Wang, Li and Paul, Jonathan and Lorenz, Uwe and Yao, Zekun}, title = {Thermal Stability of gamma' phase in long-term aged Co-Al-W alloys}, series = {Journal of Alloys and Compounds}, volume = {729}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, pages = {266 -- 276}, language = {en} } @misc{LiPyczakPauletal., author = {Li, Yuzhi and Pyczak, Florian and Paul, Jonathan and Oehring, Michael and Lorenz, Uwe and Yao, Zekun}, title = {Microstructure evolution in L12 hardened Co-base superalloys during creep}, series = {Journal of Materials Research}, volume = {32}, journal = {Journal of Materials Research}, number = {24}, issn = {2044-5326}, pages = {4522 -- 4530}, language = {en} } @misc{PaulOehringAppeletal., author = {Paul, Jonathan and Oehring, Michael and Appel, Fritz and Pyczak, Florian}, title = {Depth resolved near-surface residual stresses in γ-based TiAl before and after high-temperature exposure}, series = {Intermetallics}, volume = {84}, journal = {Intermetallics}, issn = {0966-9795}, pages = {103 -- 111}, language = {en} } @misc{SoyamaOehringEbeletal., author = {Soyama, Juliano and Oehring, Michael and Ebel, Thomas and Kainer, Karl Ulrich and Pyczak, Florian}, title = {Sintering Behavior and Microstructure Formation of Titanium Aluminide Alloys Processed by Metal Injection Molding}, series = {JOM : the journal of the Minerals, Metals \& Materials Society}, volume = {69}, journal = {JOM : the journal of the Minerals, Metals \& Materials Society}, number = {4}, issn = {1047-4838}, pages = {676 -- 682}, language = {en} } @misc{WangPyczakPauletal., author = {Wang, Li and Pyczak, Florian and Paul, Jonathan and Oehring, Michael and Lorenz, Uwe and Yao, Zekun and Ning, Yongquan}, title = {Rafting of γ′ precipitates in a Co-9Al-9W superalloy during compressive creep}, series = {Materials Science and Engineering}, volume = {719}, journal = {Materials Science and Engineering}, issn = {0921-5093}, doi = {10.1016/j.msea.2018.02.017}, pages = {43 -- 48}, language = {en} } @misc{WangOehringLorenzetal., author = {Wang, Li and Oehring, Michael and Lorenz, Uwe and Stark, Andreas and Pyczak, Florian}, title = {New insights into perovskite-Ti3AlC precipitate splitting in a Ti-45Al-5Nb-0.75C alloy by transmission electron microscopy}, series = {Intermetallics}, volume = {100}, journal = {Intermetallics}, issn = {0966-9795}, doi = {10.1016/j.intermet.2018.06.006}, pages = {70 -- 76}, language = {en} } @misc{WangOehringLorenzetal., author = {Wang, Li and Oehring, Michael and Lorenz, Uwe and Yang, Junjie and Pyczak, Florian}, title = {Influence of alloying additions on L1₂ decomposition in γ-γʹ Co-9Al-9W-2X quaternary alloys}, series = {Scripta Materialia}, volume = {154}, journal = {Scripta Materialia}, issn = {1359-6462}, pages = {176 -- 181}, language = {en} } @misc{SongWangOehringetal., author = {Song, Lin and Wang, Li and Oehring, Michael and Hu, Xingguo and Appel, Fritz and Pyczak, Florian and Zhang, Tiebang}, title = {Evidence for deformation twinning of the D019-α2 phase in a high Nb containing TiAl alloy}, series = {Intermetallics}, volume = {109}, journal = {Intermetallics}, issn = {0966-9795}, doi = {10.1016/j.intermet.2019.03.014}, pages = {91 -- 96}, language = {en} } @misc{WangSongStarketal., author = {Wang, Li and Song, Lin and Stark, Andreas and Liu, Yong and Oehring, Michael and Lorenz, Uwe and Pyczak, Florian}, title = {Identification of Laves phases in a Zr or Hf containing γ-γ′ Co-base superalloy}, series = {Journal of Alloys and Compounds}, volume = {805}, journal = {Journal of Alloys and Compounds}, issn = {0925-8388}, pages = {880 -- 886}, 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{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{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{GombolaHasemannKauffmannetal., author = {Gombola, C. and Hasemann, G. and Kauffmann, A. and Sprenger, I. and Laube, S. and Schmitt, A. and Gang, Florian and Bolbut, V. and Oehring, Michael and Blankenburg, Malte and Schell, Norbert and Staron, Peter and Pyczak, Florian and Kr{\"u}ger, Manja and Heilmaier, Martin}, title = {A zone melting device for the in-situ observation of directional solidification using high-energy synchrotron X-rays}, series = {Review of Scientific Instruments}, volume = {91}, journal = {Review of Scientific Instruments}, number = {9}, issn = {0034-6748}, pages = {9}, 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{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} } @misc{WangLiangLiuetal., author = {Wang, Li and Liang, Xiaopeng and Liu, Bin and Oehring, Michael and Paul, Jonathan David Heaton and Liu, Jie and Song, Min and Pyczak, Florian and Liu, Yong}, title = {Stacking fault formation in perovskite Ti3AlC carbides in a TiAl based alloy during creep at 800°C}, series = {Scripta Materialia}, volume = {Vol. 222}, journal = {Scripta Materialia}, issn = {1872-8456}, doi = {10.1016/j.scriptamat.2022.115034}, language = {en} } @misc{CaoWangTaoetal., author = {Cao, Xianli and Wang, Li and Tao, Hui and He, Weiwei and Liang, Xiaopeng and Liu, Bin and Oehring, Michael and Paul, Jonathan and Pyczak, Florian and Liu, Yong}, title = {Morphology evolution of P-Ti3AlC carbides and their influence on creep properties in a crept Ti-45Al-5Nb-0.75C alloy}, series = {Journal of Materials Research and Technology}, volume = {29}, journal = {Journal of Materials Research and Technology}, publisher = {Elsevier BV}, issn = {2238-7854}, doi = {10.1016/j.jmrt.2024.02.146}, pages = {4181 -- 4190}, language = {en} } @misc{WangWangPyczaketal., author = {Wang, Li and Wang, Yihao and Pyczak, Florian and Oehring, Michael and Song, Min and Liu, Yong}, title = {Revealing complex planar defects and their interactions at atomic resolution in a Laves phase containing Co-base superalloy}, series = {Acta Materialia}, volume = {264}, journal = {Acta Materialia}, publisher = {Elsevier BV}, issn = {1359-6454}, doi = {10.1016/j.actamat.2023.119568}, pages = {1 -- 20}, language = {en} } @misc{WangWangLiangetal., author = {Wang, Li and Wang, Yihao and Liang, Xiaopeng and Liu, Bin and He, Junyang and Oehring, Michael and Pyczak, Florian and Liu, Yong}, title = {Revealing the unique evolution and splitting behavior of carbides at atomic-scale in TiAl alloys : the role of elastic interactions and chemical fluctuations}, series = {Acta materialia}, volume = {296}, journal = {Acta materialia}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {1359-6454}, doi = {10.1016/j.actamat.2025.121277}, pages = {1 -- 17}, abstract = {Cubic perovskite-Ti3AlC carbides are essential strengthening particles in TiAl alloys, especially for application above 800 °C where coarsening is expected to occur. However, these carbides can decompose into small sub-particles upon extended annealing, and the underlying atomic-scale mechanisms, especially structural and compositional changes, driving this unique splitting remain unclear. This study revisits this behavior in a Ti-45Al-5Nb-0.75C alloy utilizing probe-corrected transmission electron microscopy, atom probe tomography and first-principle calculations. The results reveal that the elastic interactions significantly influence carbide evolution. While needle-like carbides transform to intact plates during aging, those in high-density regions tend to coalesce or align along elastically softest γ-matrix directions, forming low-energy plate-like carbide conglomerates. With extended annealing, periodic chemical fluctuations driven by lattice misfit, especially along the needles induce splitting. Simultaneously, a γi-phase with a larger tetragonality and a 90°-rotated c-axis relative to the γ matrix emerges between the sub-particles, which exhibits near-zero lattice mismatch with carbides along [001], combined with mass-center shifts of carbides, further stabilizing the split configurations. This study provides atomic-scale insights into the evolution and stability of strengthening precipitates in systems with tetragonal misfit, and offers new strategies for improving creep properties of TiAl alloys by tailoring carbide configurations.}, language = {en} }