Jang, Tae Jin Lee, You Na Ikeda, Yuji Koermann, Fritz Baek, Ju-Hyun Do, Hyeon-Seok Choi, Yeon Taek Gwon, Hojun Suh, Jin-Yoo Kim, Hyoung Seop Lee, Byeong-Joo Zargaran, Alireza Sohn, Seok Su 2024-01-19T09:02:59Z 2024-01-19T09:02:59Z 2023-07-13 2023-08 1359-6454 https://pubs.kist.re.kr/handle/201004/113448 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 for-mation of a single solid-solution phase is enabled by configuring various 3d-transition elements, while doping other elements even of a small portion generally leads to the formation of brittle intermetallic compounds. Herein, we demonstrate through a systematic investigation of single FCC (CoNi)100-xMox alloys that a wide range of refractory element Mo can simultaneously improve the strength and ductility while sustaining the solid-solution structure. The addition of Mo with a larger atomic size than those of 3d-transition elements in-troduces severe lattice distortion in the FCC lattice and causes grain-boundary segregation enriched by Mo atoms. In addition, increasing Mo content effectively reduces the stacking fault energy (SFE). The increased lattice distortion with Mo content enhances the solid-solution strengthening of the alloys. Besides, along with reduced SFE and stabilization of the dislocation emission site by grain-boundary segregation, this elevated solid-solution strengthening increases grain-boundary strengthening, reaching a yield strength of-1 GPa. Moreover, the reduction of SFE with increasing Mo results in the transition of dislocation substructures and the refinement of deformation twins, allowing for enhanced strain-hardening capability and thus-1.3 GPa tensile strength and-50% ductility. Such compositive and synergetic effects of refractory element Mo enable the CCAs with a single FCC solid solution to overcome the strength and ductility trade-off. English Elsevier BV Compositive role of refractory element Mo in improving strength and ductility of face-centered-cubic complex concentrated alloys Article 10.1016/j.actamat.2023.119030 1 Acta Materialia, v.255 Acta Materialia 255 N scie scopus 001013008100001 2-s2.0-85160209136 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article GRAIN-BOUNDARY SEGREGATION STACKING-FAULT ENERGIES HALL-PETCH RELATIONSHIP MECHANICAL-PROPERTIES FRICTION STRESS DEFORMATION SIZE PRECIPITATION BEHAVIOR HIGH-ENTROPY ALLOYS Complex concentrated alloy Refractory element Solid-solution strengthening Grain-boundary strengthening Strain-hardening capability