The role of trace Nb in enhancing the strength-ductility combination of a Ni2CoCrFe-based high-entropy alloy via thermo-mechanical processing

• Published in: Materials characterization Vol. 200; p. 112866
• Main Authors: Man, Jiale, Wu, Baolin, Duan, Guosheng, Zhang, Lu, Wan, Gang, Zhang, Li, Jin, Wenhan, Liu, Yandong, Esling, Claude
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.06.2023; Elsevier
• Subjects: Geometrical close-packed phase; High entropy alloy; Mechanics; Mechanics of materials; Physics; Strength-ductility combination; Thermo-mechanical processing; Topological close-packed phase; Thermo-mechanical processing; High entropy alloy; Strength-ductility combination; Geometrical close-packed phase; Topological close-packed phase
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2023.112866

In the present work, the role of trace Nb was investigated in enhancing the strength-ductility combination of the (Ni2CoCrFe)88.25(WMo)3Al5Ti3Nb0.75 high-entropy alloy. It was found that trace Nb can improve the heterogeneous microstructure, including the formation of the high-density (Ti, Nb)-rich phase instead of the (Ti, W, Mo)-rich phase, the refinement of σ and γ' phases, the production of the large amounts of stacking faults and Lomer-Cottrell locks. The strength-ductility combination of the alloy was enhanced via the improvement of the heterogeneous microstructure in thermo-mechanical processing. The results suggest that the addition of trace Nb is a promising method for enhancing the strength-ductility combination of this kind of alloys. •The (Ti, Nb)-rich phase formed instead of the (Ti, W, Mo)-rich phase.•The σ precipitated particles were refined with Nb addition.•A high density of ultra-fine γ'-LI2 precipitates formed with 4–10 nm in size.•The recrystallization was retarded due to the addition of trace Nb.•Trace Nb can improve the heterogeneous microstructure and tensile property.