AlCoCrFeNi_2.1共晶高熵合金具有优异的力学性能，在氢储存和运输等领域有着较好的应用前景。采用电化学充氢的方法对合金表面进行充氢，对充氢（H-charged）和未充氢（H-free）试样进行拉伸实验，对比两者的断口形貌特征，研究氢致析出相演变对合金力学性能的影响。结果表明：与H-free试样相比，硫酸浓度为0.5 mol/L和1.0 mol/L充氢溶液试样的屈服强度分别降低14.60%和20.22%，抗拉强度分别降低15.50%和25.15%，且随着充氢溶液中氢离子浓度的增加力学性能进一步降低，断口近表层区域表现出更明显的脆性断裂特征。充氢后发生相变的析出相在断裂过程中留在BCC相表面，形成更高、更密的凸起结构，且相界处也发现区别于两相的结构。氢致纳米析出相演变导致合金整体力学性能降低。

AlCoCrFeNi_2.1 eutectic high entropy alloy has excellent mechanical properties and promising applications in fields such as hydrogen storage and transportation. The surface of the alloy is hydrogenated by electrochemical hydrogenation， and tensile tests are carried out on H-charged and H-free specimens to compare and analyze the fracture morphology characteristics， and the effect of hydrogen-induced precipitated phase evolution on the mechanical properties of the alloy is studied. The results show that compared with the samples without hydrogen charging， the yield strength of the hydrogen charging solution samples with sulfuric acid concentrations of 0.5 mol/L and 1.0 mol/L decreases by 14.60% and 20.22%， respectively， and the tensile strength decreases by 15.50% and 25.15%， respectively. Additionally， the mechanical properties of the alloy further decrease with the increase of the hydrogen ion concentration in the hydrogen-charged solution， and the fracture region near the surface shows more obvious brittle fracture characteristics. The precipitated phase， which undergoes a phase transition after hydrogen charging， remains on the surface of the BCC phase during fracture to form a higher and denser raised structure， and a structure distinct from the two phases is also found at the phase boundary. The evolution of hydrogen-induced nanoprecipitated phases leads to a decrease in the overall mechanical properties of the alloy.