An excellent combination of strength and ductility via hierarchical precipitation structures in Co-free medium-entropy alloys

Autor: Jiaxin Zhang, Shengguo Ma, Xiaoxiao Liu, Junwei Qiao, Jianjun Wang, Dan Zhao, Zhiming Jiao, Tuanwei Zhang, Bin Xu, Zhihua Wang
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Journal of Materials Research and Technology, Vol 31, Iss , Pp 3883-3890 (2024)
Druh dokumentu: article
ISSN: 2238-7854
DOI: 10.1016/j.jmrt.2024.07.104
Popis: A Co-free non-equiatomic Ni2·5CrFeAl0·25Ti0.25 medium-entropy alloy (MEA) with an excellent strength-ductility synergy was fabricated, which shows a multiphase structure composed of face-centered cubic (FCC), L12 (ordered FCC), and Cr-rich body-centered cubic (BCC) phase by thermomechanical processing. Specifically, the aged sample displays the outstanding yield tensile strength (YTS, ∼1188 MPa), ultimate tensile strength (UTS, ∼1560 MPa) and work-hardening rate (WHR, ∼4.5 GPa) values as well as an acceptable plasticity of ∼16.6%. Theoretical calculations suggest that precipitation strengthening significantly contributes to achieving the fascinating tensile strength among various strengthening contributors. Further analyses reveal that multiple nanoscale stacking-fault (SF) networks are activated during plastic deformation in the aged alloy. Accordingly, the dual effects consisting of the hierarchical precipitation structure and SF networks lead to the combination of excellent tensile strength and strain-hardening capacity.
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