Achieving strength–ductility synergy in a non‐equiatomic Cr <sub>10</sub> Co <sub>30</sub> Fe <sub>30</sub> Ni <sub>30</sub> high‐entropy alloy with heterogeneous grain structures
Chenliang Chu, Weiping Chen, Jun-Chen Liu, Qiang Chen, Zhiqiang Fu
Abstract
Abstract Cold rolling and post‐deformation annealing (PDA) heat treatments were used to produce heterogeneous grain structures (HGS) in a single‐phase face‐centered cubic (fcc) Cr 10 Co 30 Fe 30 Ni 30 high‐entropy alloy (HEA). The microstructural evolution and microstructure–property relationship of the HEA were systematically studied under different states. HGS could be achieved in PDA‐treated samples at 875 °C for 20 s and at 900 °C for 20 s (PDA‐900‐20 s). PDA‐900‐20 s sample exhibits the most excellent combination of strength and ductility, showing a tensile yield strength of ~ 590 MPa, an ultimate strength of ~ 706 MPa and a total elongation of ~ 23.9%. Additionally, compared with the homogenized counterpart exhibiting homogenous grains, PDA‐900‐20 s sample displays a notable increment of ~ 413% in yield strength and simultaneously maintains a good ductility. The dominated strengthening mechanisms in PDA‐900‐20 s sample are grain‐boundary strengthening and heterogeneous deformation‐induced (HDI) strengthening, whereas the good ductility is mainly resulted from the HDI ductility. Accordingly, the present study provides an effective and simple pathway to overcome the strength–ductility trade‐off of typical fcc HEAs through heterogeneous microstructure.