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Schneider, Mike (author), Couzinié, Jean Philippe (author), Shalabi, Amin (author), Ibrahimkhel, Farhad (author), Ferrari, A. (author), Körmann, F.H.W. (author), Laplanche, Guillaume (author)This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and...journal article 2024
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Ferrari, A. (author), Körmann, F.H.W. (author), Asta, Mark (author), Neugebauer, Jörg (author)In multicomponent materials, short-range order (SRO) is the development of correlated arrangements of atoms at the nanometer scale. Its impact in compositionally complex materials has stimulated an intense debate within the materials science community. Understanding SRO is critical to control the properties of technologically relevant...review 2023
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Srinivasan, P. (author), Shapeev, Alexander (author), Neugebauer, Jörg (author), Körmann, F.H.W. (author), Grabowski, Blazej (author)Explicit anharmonicity, defined as the vibrational contribution beyond the quasiharmonic approximation, is qualitatively different between the group V and group VI bcc refractory elements. Group V elements show a small and mostly negative anharmonic entropy, whereas group VI elements have a large positive anharmonic entropy, strongly...journal article 2023
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Jang, Tae Jin (author), Lee, You Na (author), Ikeda, Yuji (author), Körmann, F.H.W. (author), Baek, Ju Hyun (author), Do, Hyeon Seok (author), Choi, Yeon Taek (author), Gwon, Hojun (author), Suh, Jin Yoo (author), Kim, Hyoung Seop (author), Lee, Byeong Joo (author), Zargaran, Alireza (author), Sohn, Seok Su (author)Complex concentrated alloys (CCAs) with a face-centered-cubic (FCC) structure exhibit remarkable mechanical properties, introducing the expansion of compositional space in alloy design for structural materials. The formation of a single solid-solution phase is enabled by configuring various 3d-transition elements, while doping other elements...journal article 2023
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Rao, Ziyuan (author), Tung, Po Yen (author), Xie, Ruiwen (author), Wei, Ye (author), Ferrari, A. (author), Klaver, T.P.C. (author), Körmann, F.H.W. (author), Li, Zhiming (author), Bauer, Stefan (author), Raabe, Dierk (author)High-entropy alloys are solid solutions of multiple principal elements that are capable of reaching composition and property regimes inaccessible for dilute materials. Discovering those with valuable properties, however, too often relies on serendipity, because thermodynamic alloy design rules alone often fail in high-dimensional composition...journal article 2022
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Wagner, Christian (author), Ferrari, A. (author), Schreuer, Jürgen (author), Couzinié, Jean Philippe (author), Ikeda, Yuji (author), Körmann, F.H.W. (author), Eggeler, Gunther (author), George, Easo P. (author), Laplanche, Guillaume (author)Physical properties of ten single-phase FCC Cr<sub>x</sub>Mn<sub>20</sub>Fe<sub>20</sub>Co<sub>20</sub>Ni<sub>40-</sub><sub>x</sub> high-entropy alloys (HEAs) were investigated for 0 ≤ x ≤ 26 at%. The lattice parameters of these alloys were nearly independent of composition while solidus temperatures increased linearly by ∼30 K as x increased...journal article 2022
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Novikov, Ivan (author), Grabowski, Blazej (author), Körmann, F.H.W. (author), Shapeev, Alexander (author)We present the magnetic Moment Tensor Potentials (mMTPs), a class of machine-learning interatomic potentials, accurately reproducing both vibrational and magnetic degrees of freedom as provided, e.g., from first-principles calculations. The accuracy is achieved by a two-step minimization scheme that coarse-grains the atomic and the spin space...review 2022
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Chung, Hyun (author), Kim, Dae Woong (author), Cho, Woo Jin (author), Han, Heung Nam (author), Ikeda, Yuji (author), Ishibashi, Shoji (author), Körmann, F.H.W. (author), Sohn, Seok Su (author)High- and medium-entropy alloys (HEAs and MEAs) possess high solid-solution strength. Numerous investigations have been conducted on its impact on yield strength, however, there are limited reports regarding the relation between solid-solution strengthening and strain-hardening rate. In addition, no attempt has been made to account for the...journal article 2022
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Zhou, Ying (author), Srinivasan, Prashanth (author), Körmann, F.H.W. (author), Grabowski, Blazej (author), Smith, Roger (author), Goddard, Pooja (author), Duff, Andrew Ian (author)Multi-principal-component alloys have attracted great interest as a novel paradigm in alloy design, with often unique properties and a vast compositional space auspicious for materials discovery. High entropy alloys (HEAs) belong to this class and are being investigated for prospective nuclear applications with reported superior mechanical...journal article 2022
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Ghosh, Sheuly (author), Sotskov, Vadim (author), Shapeev, Alexander V. (author), Neugebauer, Jörg (author), Körmann, F.H.W. (author)We present an analysis of temperature-dependent atomic short-range ordering and phase stability of the face-centered cubic CrCoNi medium-entropy alloy employing a combination of ab initio calculations and on-lattice machine learning interatomic potentials. Temperature-dependent properties are studied with canonical Monte Carlo simulations. At...journal article 2022
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Rao, Ziyuan (author), Dutta, B. (author), Körmann, F.H.W. (author), Lu, Wenjun (author), Zhou, Xuyang (author), Liu, Chang (author), da Silva, Alisson Kwiatkowski (author), Wiedwald, Ulf (author), Spasova, Marina (author), Farle, Michael (author), Ponge, Dirk (author), Gault, Baptiste (author), Neugebauer, Jörg (author), Raabe, Dierk (author), Li, Zhiming (author)Since its first emergence in 2004, the high-entropy alloy (HEA) concept has aimed at stabilizing single- or dual-phase multi-element solid solutions through high mixing entropy. Here, this strategy is changed and renders such massive solid solutions metastable, to trigger spinodal decomposition for improving the alloys’ magnetic properties....journal article 2021
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Oh, Hyun Seok (author), Odbadrakh, Khorgolkhuu (author), Ikeda, Yuji (author), Mu, Sai (author), Körmann, F.H.W. (author), Sun, Cheng Jun (author), Ahn, Heh Sang (author), Yoon, Kook Noh (author), Ma, Duancheng (author), Tasan, Cemal Cem (author), Egami, Takeshi (author), Park, Eun Soo (author)Complex concentrated alloys (CCAs) are of growing interest due to their outstanding mechanical properties that exceed the property limits of conventional alloys. Whereas the superior properties are often attributed to severe lattice distortion, to date it is not clear what controls the lattice distortion and how it affects the mechanical...journal article 2021
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Körmann, F.H.W. (author), Kostiuchenko, Tatiana (author), Shapeev, Alexander (author), Neugebauer, Jörg (author)The phase stability of a bcc AlNbTiV high-entropy alloy at elevated temperatures is studied using a combination of machine-learning interatomic potentials, first-principles calculations, and Monte Carlo simulations. The simulations reveal a B2 ordering below about 1700 K, mainly caused by a strong site preference of Al and Ti. A much weaker...journal article 2021
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Pei, Zongrui (author), Dutta, B. (author), Körmann, F.H.W. (author), Chen, Mingwei (author)Negative stacking fault energies (SFEs) are found in face-centered cubic high-entropy alloys with excellent mechanical properties, especially at low temperatures. Their roles remain elusive due to the lack of in situ observation of nanoscale deformation. Here, the polymorphism of Shockley partials is fully explored, assisted by a new method....journal article 2021
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Gubaev, Konstantin (author), Ikeda, Yuji (author), Tasnádi, Ferenc (author), Neugebauer, Jörg (author), Shapeev, Alexander V. (author), Grabowski, Blazej (author), Körmann, F.H.W. (author)An active learning approach to train machine-learning interatomic potentials (moment tensor potentials) for multicomponent alloys to ab initio data is presented. Employing this approach, the disordered body-centered cubic (bcc) TiZrHfTax system with varying Ta concentration is investigated via molecular dynamics simulations. Our results show...journal article 2021
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Jang, Tae Jin (author), Choi, Won Seok (author), Kim, Dae Woong (author), Choi, Gwanghyo (author), Jun, Hosun (author), Ferrari, A. (author), Körmann, F.H.W. (author), Choi, Pyuck Pa (author), Sohn, Seok Su (author)Precipitation strengthening has been the basis of physical metallurgy since more than 100 years owing to its excellent strengthening effects. This approach generally employs coherent and nano-sized precipitates, as incoherent precipitates energetically become coarse due to their incompatibility with matrix and provide a negligible...journal article 2021
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Ferrari, A. (author), Körmann, F.H.W. (author)Besides revealing excellent mechanical properties, compositionally complex alloys are also very promising candidates for applications in heterogeneous catalysis. The opportunity provided by the tremendously large composition phase space to explore new materials and tune the materials properties in the materials design cycle is, however,...journal article 2021
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Yang, Dae Cheol (author), Jo, Yong Hee (author), Ikeda, Yuji (author), Körmann, F.H.W. (author), Sohn, Seok Su (author)Multi-principal element alloys usually exhibit outstanding strength and toughness at cryogenic temperatures, especially in CrMnFeCoNi and CrCoNi alloys. These remarkable cryogenic properties are attributed to the occurrence of deformation twins, and it is envisaged that a reduced stacking fault energy (SFE) transforms the deformation...journal article 2021
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Zhu, Li Fang (author), Janssen, Jan (author), Ishibashi, Shoji (author), Körmann, F.H.W. (author), Grabowski, Blazej (author), Neugebauer, Jörg (author)The interface method is a well established approach for predicting melting points of materials using interatomic potentials. However, applying the interface method is tedious and involves significant human intervention. The whole procedure involves several successive tasks: estimate a rough melting point, set up the interface structure, run...journal article 2021
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Ikeda, Yuji (author), Gubaev, Konstantin (author), Neugebauer, Jörg (author), Grabowski, Blazej (author), Körmann, F.H.W. (author)Recent experiments show that the chemical composition of body-centered cubic (bcc) refractory high entropy alloys (HEAs) can be tuned to enable transformation-induced plasticity (TRIP), which significantly improves the ductility of these alloys. This calls for an accurate and efficient method to map the structural stability as a function of...journal article 2021