Influence of V and Al in enhancing the strength and ductility of Co-rich high-entropy alloys

JF Zou and RK Nutor and QP Cao and XD Wang and SQ Ding and DX Zhang and ZW Dai and JZ Jiang, JOURNAL OF ALLOYS AND COMPOUNDS, 948, 169745 (2023).

DOI: 10.1016/j.jallcom.2023.169745

Since the proposal of face-centered cubic (fcc)-structured high entropy alloys (HEAs) almost two decades ago, multiple compositional combinations have been significantly developed, exhibiting exceptional me-chanical properties. In this study, we propose a strategy for developing an fcc-structured Co-rich Co40Fe25V20Ni15 HEA by incorporating V instead of Cr to take advantage of its efficient strengthening effect. The newly developed HEA possesses solid-solution strength (sigma o) and Hall-Petch coefficient (ky) of 204 +/- 13 MPa and 955 +/- 60 MPa center dot mu m1/2. The estimated ky is the highest amongst all fcc-structured HEAs and indicates a high grain boundary strengthening effect. Additional minor alloying with Al further en- hances the mechanical performance of the alloy via precipitation- strengthening effects which exhibit comparable mechanical properties as Ni-based superalloys. Microstructural analyses of the deformation microstructures for the Al-free and Al-containing Co-rich samples reveal that deformation twinning is prevalent at 298 K and 77 K. The present study further demonstrates the importance of utilizing V and Al in developing high-performance alloys.(c) 2023 Elsevier B.V. All rights reserved.

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