Non-equal molar high entropy alloys (HEAs) are promising to obtain better mechanical properties owing to abundant composition designs compared with single equal molar HEAs point. Co_xFe_50−xCr₂₅Ni₂₅ HEAs were designed to investigate the effect of Co compositional variation on the structure and mechanical properties of single phase solid solutions. Microstructure evolution at different strain levels was studied by electron backscatter diffraction. The results indicate that lattice parameter tends to decrease and yield strength are enhanced, with the increase of Co content. The ultimate tensile strength and ductility are improved at Co 30–35 at%, especially the ductility, compared to the equal molar CoCrFeNi HEAs. Meanwhile, grain rotation is slower and more difficult in non-equal molar Co₃₅Fe₁₅, and the greater low angle boundary fraction indicates the higher dislocation density. In different deformation stages, the dislocation forest strengthening and twinning-induced plasticity effect result in better strength-ductility combination in Co₃₅Fe₁₅.

非均等摩尔高熵合金（HEA）由于与单一等摩尔HEA点相比具有丰富的成分设计，有望获得更好的机械性能。Co _x Fe _50−x Cr ₂₅ Ni ₂₅HEA旨在研究Co组成变化对单相固溶体结构和力学性能的影响。通过电子反向散射衍射研究了在不同应变水平下的显微组织演变。结果表明，随着Co含量的增加，晶格参数趋于降低，屈服强度提高。与等摩尔CoCrFeNi HEA相比，在Co 30–35 at％时，极限抗拉强度和延展性得到了改善，尤其是延展性。同时，在不等摩尔的Co ₃₅ Fe _15中，晶粒旋转更慢且更困难，低角度边界分数越大，表明位错密度越高。在不同的变形阶段，错位森林的强化和孪生诱导的可塑性效应导致Co ₃₅ Fe ₁₅中更好的强度-延展性组合。