TY - GEN A1 - Wang, Li A1 - Wang, Yihao A1 - Pyczak, Florian A1 - Oehring, Michael A1 - Song, Min A1 - Liu, Yong T1 - Revealing complex planar defects and their interactions at atomic resolution in a Laves phase containing Co-base superalloy T2 - Acta Materialia Y1 - 2024 U6 - https://doi.org/10.1016/j.actamat.2023.119568 SN - 1359-6454 VL - 264 SP - 1 EP - 20 PB - Elsevier BV ER - TY - GEN A1 - Tang, Yingchun A1 - Li, Changle A1 - Lu, Song A1 - Li, Wei A1 - Vitos, Levente A1 - Pyczak, Florian T1 - Magneto-chemical effects in the elastic properties of Co3Al-based compounds T2 - Materials Today Communications Y1 - 2024 U6 - https://doi.org/10.1016/j.mtcomm.2024.110507 SN - 2352-4928 VL - 41 SP - 1 EP - 11 PB - Elsevier BV ER - TY - GEN A1 - Heidari Pebdani, Zeinab A1 - Janisch, Rebecca A1 - Pyczak, Florian T1 - Effect of V-VIB group ternary elements on the properties of Ti2AlM-type O-phases: A first-principles study T2 - Computational Condensed Matter Y1 - 2024 U6 - https://doi.org/10.1016/j.cocom.2024.e00945 SN - 2352-2143 VL - 40 PB - Elsevier BV ER - TY - GEN A1 - Gupta, Vipul A1 - Paul, Jonathan David Heaton A1 - Schmitt, Ingo A1 - Pyczak, Florian T1 - SciLitMiner : an intelligent system for scientific literature mining and knowledge discovery T2 - Advanced intelligent systems N2 - Recent advances in data mining have enabled automation in literature‐based discovery (LBD), allowing synergistic evaluation of experimental findings reported in scientific publications. However, existing tools and digital libraries fall short in generating relevant literature collections and evaluating them for highly specific questions. This article presents SciLitMiner, an intelligent system to address this gap. SciLitMiner enables federated ingestion of literature from digital libraries; applies advanced retrieval techniques, including dataset‐aware retrieval from visual elements, to identify relevant studies; and leverages retrieval‐augmented generation (RAG) tailored to domain‐specific knowledge reasoning. The system is applied in materials science to study the creep behavior of γ‐TiAl alloys, revealing the intricate interplay between material, process, microstructure, and creep rate, represented through knowledge graphs. Two domain experts rate responses from the knowledge reasoning workflow with OpenAI large language models (LLMs) as the backbone above “good” (3 on a 5‐point Likert scale) in over 90% across qualitative criteria, indicating strong performance. In a case study, the workflow also outperforms gpt‐4.5‐turbo with web search and other leading tools in reliability. A second case study benchmarks open‐source LLMs as drop‐in replacements for proprietary models, demonstrating comparable‐to‐superior performance. The system's flexibility enables its use in automated LBD across diverse research domains. Y1 - 2025 U6 - https://doi.org/10.1002/aisy.202501235 SN - 2640-4567 SP - 1 EP - 20 PB - Wiley CY - Weinheim ER - TY - GEN A1 - Liu, Xu A1 - Song, Lin A1 - Pyczak, Florian A1 - Stark, Andreas A1 - Wang, Li A1 - Guo, Xiang A1 - Zhang, Tiebang T1 - Stress-induced orthorhombic O phase in TiAl alloys T2 - Acta materialia N2 - The orthorhombic O phase precipitation within the D019-α2 phase has attracted increasing attention recently in high Nb containing TiAl (high Nb-TiAl) alloys since the precipitation temperature is close to the expected service temperature of the alloys. In this study, in-situ synchrotron high energy X-ray diffraction (HEXRD) reveals that the O phase precipitates at 550 °C while it dissolves into the α2 phase at 750 °C during heat treatments. However, under external stress the O phase unexpectedly precipitates from α2 phase at 800 °C and even 900 °C. The O phase formation proceeds further in the presence of a critical stress promoted by internal stress accumulation in the α2 phase, whereas the reverse O→α2 phase transformation takes place when the internal stresses are relaxed. Additionally, it has been revealed that the O phase preferentially precipitates from specifically oriented α2 grains with one of their <110> directions aligned perpendicular and their 〈0001〉 directions rotated by an angle of 120° out of the external load axis. This α2 phase orientation facilitates the α2→O crystal transition during uniaxial compression. Transmission electron microscopy (TEM) study shows that stress-induced α2→O transformation is governed by small atomic shifts in the α2 lattice. In addition, the selective growth of certain O variants via shuffling along an [110]α2 direction is found to accommodate the external strain component in this direction. KW - Titanium aluminides KW - Phase transformation KW - Strain accumulation KW - Variant selection KW - Hot compression Y1 - 2025 U6 - https://doi.org/10.1016/j.actamat.2025.120751 SN - 1359-6454 VL - 286 SP - 1 EP - 13 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Stark, Andreas A1 - Rackel, Marcus W. A1 - Pyczak, Florian T1 - How rapid heating and quenching cycles affect phase evolution in advanced γ-TiAl alloys : an in situ synchrotron radiation study T2 - MRS communications N2 - Additive manufacturing (AM) processes are increasingly considered as an alternative manufacturing route to produce complex aircraft components out of γ-TiAl-based alloys. Due to the process-related high and short-time energy input, extremely fast heating and cooling rates occur which can result in thermodynamic and chemical disequilibrium. We studied the effect of rapid heating and quenching cycles in a Ti–48Al–2Nb–2Cr (in at.%) alloy by carrying out in situ high-energy X-ray diffraction experiments in which AM-related heating cycles were simulated. These in situ experiments allow to determine the influence of cooling rate and a chosen powder bed temperature on phase evolution. Y1 - 2025 U6 - https://doi.org/10.1557/s43579-025-00756-3 SN - 2159-6867 VL - 15 IS - 4 SP - 790 EP - 795 PB - Springer Science and Business Media LLC CY - Berlin ER - TY - GEN A1 - Stark, Andreas A1 - Lott, Dieter A1 - Pyczak, Florian T1 - A dilatometer and in situ synchrotron X-ray diffraction study : α-quenching and reheating of a Nb-rich titanium aluminide alloy T2 - MRS advances N2 - Intermetallic γ-TiAl-based alloys are currently used as structural materials for turbine blades in aero engines. Additive manufacturing is increasingly considered as an additional manufacturing route for components consisting of γ titanium aluminides; however, the high heating and cooling rates result in chemical and thermodynamical disequilibrated microstructures. In our study, in situ synchrotron X-ray diffraction was applied to follow the formation of the disequilibrium microstructure during quenching and to study its re-equilibration during a subsequent annealing treatment in a Nb-rich γ-TiAl-based alloy. The quenched sample showed an incomplete massive transformation, with large remaining α2 grains. During reheating, the analysis of the collected data showed that equilibration of the quenched microstructure takes place in several reordering and transformation steps, e.g., orthorhombic distortion of the hexagonal α2 phase (around 550 °C), almost complete transformation of the supersaturated quenched α2 to γ (around 850 °C), and retransformation of γ to new α2 (around 1050 °C). Y1 - 2025 U6 - https://doi.org/10.1557/s43580-025-01382-w SN - 2731-5894 VL - 10 IS - 14 SP - 1767 EP - 1772 PB - Springer Science and Business Media LLC CY - Cham ER - TY - GEN A1 - Liu, Shen A1 - Liu, Xu A1 - Wu, Qiaohan A1 - Li, Yixuan A1 - Shi, Qiuyi A1 - Song, Lin A1 - Pyczak, Florian A1 - Stark, Andreas A1 - Li, Xiaobing A1 - Zhang, Tiebang T1 - In-situ synchrotron high energy X-ray diffraction study on the internal strain evolution of an extruded Ti-45Al-8Nb-0.2C alloy during high-temperature compression T2 - Materials characterization N2 - Due to their exceptional properties, γ-TiAl based alloys present substantial prospect for aerospace and automotive applications. However, the significant disparity in plasticity between the D019-α2 and L10-γ phases greatly affects TiAl alloys' service behavior. This study investigates the internal strain accumulation in the α2 and γ phases of an extruded Ti-45Al-8Nb-0.2C alloy during compression at 900 °C and the subsequent stress relaxation behavior during annealing at 850 °C, using in situ synchrotron high-energy X-ray diffraction (HEXRD). During compression, the γ phase starts to yield plastically at approximately 410 MPa true stress, progressively shifting the load to the α2 phase and generating high residual stress in the α2 phase after deformation. However, annealing at 850 °C for 30 min only partially relieves the residual stress in the α2 phase, with the relaxation rate decreasing substantially after the first 10 min. Furthermore, when the true stress reaches 790 MPa during compression, the α2 phase undergoes rigid-body rotation to accommodate the plastic deformation of the adjacent γ phase, initiating texture evolution that ultimately forms a distinct fiber texture. KW - High Nb-TiAl alloy KW - Synchrotron radiation KW - Lattice strain KW - Stress relaxation KW - Fiber texture Y1 - 2025 U6 - https://doi.org/10.1016/j.matchar.2025.115746 SN - 1044-5803 VL - 230 SP - 1 EP - 12 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Wang, Li A1 - Wang, Yihao A1 - Liang, Xiaopeng A1 - Liu, Bin A1 - He, Junyang A1 - Oehring, Michael A1 - Pyczak, Florian A1 - Liu, Yong T1 - Revealing the unique evolution and splitting behavior of carbides at atomic-scale in TiAl alloys : the role of elastic interactions and chemical fluctuations T2 - Acta materialia N2 - 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. KW - Titanium aluminides KW - Carbides KW - Morphology KW - Elastic interaction KW - STEM HAADF Y1 - 2025 U6 - https://doi.org/10.1016/j.actamat.2025.121277 SN - 1359-6454 VL - 296 SP - 1 EP - 17 PB - Elsevier BV CY - Amsterdam ER -