Addition of Mo to the face-centered cubic (fcc) NiCoCrFe base alloy is an attractive method for improving the solid-solution strengthening of high-entropy alloys (HEAs). However, the low solubility of Mo in the equiatomic base alloy limits implementation. In this study, we used thermodynamic and ab initio calculations to develop an off-equiatomic NiCoCrFe-based HEA with an Mo content of up to 11.11 at%. Thermodynamic phase diagrams were constructed for the derived quinary subsystems with various Mo contents, and potential precipitate-free HEA compositions were determined. The degrees of lattice distortion (DLD) in seven selected HEAs were evaluated by statistically analyzing bond lengths determined using ab initio calculations. This approach could accurately predict the relative magnitudes of DLDs for multiple off-equiatomic HEAs in the studied system. Consequently, an off-equiatomic Ni_1.8Co_0.95Cr_0.8Fe_0.25Mo_0.475 HEA was designed with enhanced lattice distortion, solid-solution strengthening, and yield strength. Microscopic analysis confirmed that the designed HEA exhibited a single fcc lattice, while excess Mo was detected at the grain boundary (GB) in a coarse-grained sample. It was deduced that slight GB segregation had a negligible influence on the lattice concentrations and solid-solution strengthening.

将Mo添加到面心立方（fcc）NiCoCrFe基合金中是提高高熵合金（HEA）固溶强化的一种有吸引力的方法。然而，Mo在等原子基合金中的低溶解度限制了其实现。在这项研究中，我们使用热力学和从头算的方法开发了Mo含量高达11.11 at％的非等原子NiCoCrFe基HEA。构造了具有各种Mo含量的衍生五元子系统的热力学相图，并确定了潜在的无沉淀HEA组成。通过从头算确定的键合长度的统计分析，评估了七个选定的HEA中的晶格畸变（DLD）程度计算。这种方法可以准确地预测所研究系统中多个非等原子HEA的DLD的相对大小。因此，设计了一种具有非等原子性的Ni _1.8 Co _0.95 Cr _0.8 Fe _0.25 Mo _0.475 HEA，具有增强的晶格畸变，固溶强化和屈服强度。显微分析证实，设计的HEA表现出单个fcc晶格，而在粗粒样品中的晶界（GB）处检测到过量的Mo。可以推断，轻微的GB偏析对晶格浓度和固溶强化的影响可忽略不计。