TY - GEN A1 - Wang, Li A1 - Oehring, Michael A1 - Li, Yuzhi A1 - Song, Lin A1 - Liu, Yon A1 - Stark, Andreas A1 - Lorenz, Uwe A1 - Pyczak, Florian T1 - Microstructure, phase stability and element partitioning of γ/γʹ Co-9Al-9W-2X alloys in different annealing conditions T2 - Journal of Alloys and Compounds Y1 - 2019 SN - 0925-8388 VL - 787 SP - 594 EP - 605 ER - TY - GEN A1 - Lazurenko, Daria V. A1 - Laptev, Ilia S. A1 - Golkovsky, Mikhail G. A1 - Stark, Andreas A1 - Paul, Jonathan A1 - Bataev, Ivan A. A1 - Ruktuev, Alexey A. A1 - Song, Lin A1 - Gollwitzer, Christian A1 - Pyczak, Florian T1 - Influence of the Ti/Al/Nb ratio on the structure and properties on intermetallic layers obtained on titanium by non-vacuum electron beam cladding T2 - Materials Characterization Y1 - 2020 SN - 1044-5803 VL - 163 ER - TY - GEN A1 - Song, Lin A1 - Appel, Fritz A1 - Liu, Wenhao A1 - Pyczak, Florian A1 - Zhang, Tiebang T1 - {11¯01} tension twins and {11¯01}-{22¯01}/{22¯01}-{11¯01} double twins in the D019 ordered hexagonal α2-Ti3Al phase T2 - Acta Materialia Y1 - 2023 U6 - https://doi.org/10.1016/j.actamat.2023.119335 VL - 260 IS - 3 ER - TY - GEN A1 - Guo, Xiang A1 - Song, Lin A1 - Liu, Xu A1 - Stark, Andreas A1 - Pyczak, Florian A1 - Zhang, Tiebang T1 - In-situ synchrotron HEXRD study on the phase transformation mechanisms of the ω-related phases in a Ti4Al3Nb alloy T2 - Materials Characterization Y1 - 2023 U6 - https://doi.org/10.1016/j.matchar.2023.112901 SN - 1873-4189 SN - 1044-5803 VL - Vol. 200 ER - TY - GEN A1 - Liu, Xu A1 - Song, Lin A1 - Stark, Andreas A1 - Pyczak, Florian A1 - Zhang, Tiebang T1 - In-situ synchrotron high energy X-ray diffraction study on the deformation mechanisms of D019-α2 phase during high-temperature compression in a TiAl alloy T2 - Journal of Materials Research and Technology Y1 - 2024 U6 - https://doi.org/10.1016/j.jmrt.2024.10.231 SN - 2238-7854 VL - 33 SP - 5850 EP - 5862 PB - Elsevier BV ER - TY - GEN A1 - Berto, Federico A1 - Hua, Chuanbo A1 - Park, Junyoung A1 - Luttmann, Laurin A1 - Ma, Yining A1 - Bu, Fanchen A1 - Wang, Jiarui A1 - Ye, Haoran A1 - Kim, Minsu A1 - Choi, Sanghyeok A1 - Zepeda, Nayeli Gast A1 - Hottung, André A1 - Zhou, Jianan A1 - Bi, Jieyi A1 - Hu, Yu A1 - Liu, Fei A1 - Kim, Hyeonah A1 - Son, Jiwoo A1 - Kim, Haeyeon A1 - Angioni, Davide A1 - Kool, Wouter A1 - Cao, Zhiguang A1 - Zhang, Qingfu A1 - Kim, Joungho A1 - Zhang, Jie A1 - Shin, Kijung A1 - Wu, Cathy A1 - Ahn, Sungsoo A1 - Song, Guojie A1 - Kwon, Changhyun A1 - Tierney, Kevin A1 - Xie, Lin A1 - Park, Jinkyoo T1 - RL4CO : an extensive reinforcement learning for combinatorial optimization benchmark T2 - KDD '25 : proceedings of the 31st ACM SIGKDD Conference on Knowledge Discovery and Data Mining V.2 N2 - Combinatorial optimization (CO) is fundamental to several real-world applications, from logistics and scheduling to hardware design and resource allocation. Deep reinforcement learning (RL) has recently shown significant benefits in solving CO problems, reducing reliance on domain expertise and improving computational efficiency. However, the absence of a unified benchmarking framework leads to inconsistent evaluations, limits reproducibility, and increases engineering overhead, raising barriers to adoption for new researchers. To address these challenges, we introduce RL4CO, a unified and extensive benchmark with in-depth library coverage of 27 CO problem environments and 23 state-of-the-art baselines. Built on efficient software libraries and best practices in implementation, RL4CO features modularized implementation and flexible configurations of diverse environments, policy architectures, RL algorithms, and utilities with extensive documentation. RL4CO helps researchers build on existing successes while exploring and developing their own designs, facilitating the entire research process by decoupling science from heavy engineering. We finally provide extensive benchmark studies to inspire new insights and future work. RL4CO has already attracted numerous researchers in the community and is open-sourced at https://github.com/ai4co/rl4co. Y1 - 2025 SN - 979-8-4007-1454-2 U6 - https://doi.org/10.1145/3711896.3737433 SP - 5278 EP - 5289 PB - ACM CY - New York, NY, USA 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 - 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 -