Multiscale plastic deformation in additively manufactured FeCoCrNiMox high-entropy alloys to achieve strength–ductility synergy at elevated temperatures

• Published in: International journal of plasticity 2024-12, Vol.183, Article 104142
• Main Authors: Lin, Danyang, Hu, Jixu, Wu, Renhao, Liu, Yazhou, Li, Xiaoqing, SaGong, Man Jae, Tan, Caiwang, Song, Xiaoguo, Kim, Hyoung Seop
• Format: Article
• Language: English
• Subjects: Additively manufactured FeCoCrNiMox; Deformation twinning; Elevated temperature; Molecular dynamics simulation; Multiscale plastic deformation
• ISSN: 0749-6419
• DOI: 10.1016/j.ijplas.2024.104142

•Defect-free FeNiCrCoMox high-entropy alloys fabricated by laser powder bed fusion.•The Mo-doped HEAs exhibit multiscale strengthening mechanisms.•Mo reduces the stacking fault energy at 25 °C, promoting twinning.•At 600 °C, twinning is exclusively observed in FeNiCrCoMo0.3 and FeNiCrCoMo0.5.•An addition of 7–11 at% Mo facilitates strength–ductility synergy at 600 °C. The application of structural metals in extreme environments necessitates materials with superior mechanical properties. Mo-doped FeCoCrNi high-entropy alloys (HEAs) have emerged as potential candidates for use in such demanding environments. This study investigates the high-temperature performance of FeCoCrNiMox HEAs with varying Mo contents (x = 0, 0.1, 0.3, and 0.5) prepared by laser powder bed fusion additive manufacturing. The mechanical properties were evaluated at room and 600 °C temperatures, and the microstructures were characterized using scanning electron microscopy, electron backscatter diffraction, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The intrinsic dislocation cell patterning, solid-solution strengthening, nanoprecipitation, and twinning effects collectively modulated the plastic deformation behavior of the samples. The high-temperature mechanical performance was comprehensively analyzed in conjunction with ab initio calculations and molecular dynamics simulations to reveal the origin of the experimentally observed strength–ductility synergy of FeCoCrNiMo0.3. This study has significant implications for FeCoCrNiMox HEAs and extends our understanding of the structural origins of the exceptional mechanical properties of additively manufactured HEAs. [Display omitted]