FeCoNi, V_0.85FeCoNi, FeCoNiCu_1.15 and V_0.85FeCoNiCu_1.15 alloys have been synthesized by arc melting and analyzed by powder X-ray diffraction, electron microscopy, magnetic measurements, and density functional theory (DFT). The influence of each alloying element on the magnetic exchange interaction, Curie temperature (T_C) and magnetocaloric effect is evaluated. The experimental results show that Cu and V “dilute” the magnetic properties and couple antiferromagnetically to Fe, Co, and Ni. Analysis of the microstructure reveals a lack of solubility between V and Cu with FeCoNi, and between themselves, thus lowering the concentration of V and Cu in the main solid solution of the 5-element alloy V_0.85FeCoNiCu_1.15. T_c decreases significantly from 997 K in FeCoNi to 245 K in V_0.85FeCoNi and 297 K in V_0.85FeCoNiCu_1.15, respectively. The derivative of magnetization as a function of temperature (dM/dT) in the vicinity of T_c is drastically reduced due to the presence of V which indicates a reduced magnetocaloric effect. DFT calculations confirm antiferromagnetic coupling of V to the ferromagnetic FeCoNi-base and predict a similar behavior for other transition metal elements (e.g., Ti, Cr, Mn). This leads to a lowering of T_c, which is needed to establish the magnetocaloric effect at room temperature. However, it comes at a cost of reduced magnetic moments. Nevertheless, the use of V and Cu has shown possible routes for tuning the magnetocaloric effect in FeCoNi-based high entropy alloys.

FeCoNi、V _0.85 FeCoNi、FeCoNiCu _1.15和 V _0.85 FeCoNiCu _1.15合金已通过电弧熔炼合成，并通过粉末 X 射线衍射、电子显微镜、磁测量和密度泛函理论 (DFT) 进行了分析。评估了每种合金元素对磁​​交换相互作用、居里温度 (T _C ) 和磁热效应的影响。实验结果表明，Cu 和 V“稀释”了磁性，并反铁磁耦合到 Fe、Co 和 Ni。微观结构分析表明，V 和 Cu 与 FeCoNi 之间以及它们之间缺乏溶解度，从而降低了五元合金 V 主固溶体中 V 和 Cu 的浓度_0.85铁钴镍铜_1.15 . T _c分别从FeCoNi中的997 K显着降低到V _0.85 FeCoNi中的245 K和V _0.85 FeCoNiCu _{1.15中的297 K。}由于 V 的存在，表明磁热效应降低，在 Tc 附近作为温度函数的磁化导数 (dM/dT) 急剧_降低。DFT 计算证实了 V 与铁磁 FeCoNi 基体的反铁磁耦合，并预测了其他过渡金属元素（例如Ti、Cr、Mn）的类似行为。_{这导致 T c}降低，这是在室温下建立磁热效应所必需的。然而，它是以减少磁矩为代价的。然而，V 和 Cu 的使用显示了调整 FeCoNi 基高熵合金中磁热效应的可能途径。