【摘要】 本工作通过激光熔化沉积技术制备了Al_xCoCrFeNi （x=0,0.3,0.5）系高熵合金，并研究了Al的添加对激光熔化沉积CoCrFeNi合金的物相结构、组织形貌及性能的影响规律。研究结果表明：Al₀与Al_0.3高熵合金的微观结构为单相FCC结构固溶体，而Al_0.5高熵合金的微观结构为在FCC相基底的晶界/枝晶界处析出富集Al、 Ni原子的B2相。合金样品的拉伸力学性能表明：Al_0.5CoCrFeNi高熵合金的屈服强度达到了原合金的2.66倍（140～372 MPa）,抗拉强度达到约716 MPa,延伸率约为40%;电化学极化曲线分析表明，Al_xCoCrFeNi系高熵合金在1 mol/L的H₂SO₄溶液中均具有显著的稳定钝化区，Al添加引起的致钝电流和维钝电流随着Al含量的增加呈现先减小后增大的趋势。更多还原

【Abstract】 In this work, laser melting deposition technology（LMD） has been exploited to manufactured Al_xCoCrFeNi（x=0, 0.3, and 0.5, denoted as Al_x hereafter）, and the impacts of Al addition on phase structure, microstructure, and performance of LMD-CoCrFeNi alloys were investigated. The results indicate that the microstructure of Al₀ and Al_0.3 consists of a single-phase FCC solid solution, whereas the one in Al_0.5 is composed of a B2 phase enriched Al and Ni atoms precipitated at the grain boundary/dendritic grain boundary for the FCC phase matrix. The tensile mechanical properties of the alloy samples showed that the yield strength of the Al_0.5CoCrFeNi high entropy alloy reached 2.66 times of the original alloy（140—372 MPa）, the tensile strength reached ～716 MPa, and the elongation was ～40%. The electrochemical polarization curve analysis shows that a prominently stable passivation region represents in the Al_xCoCrFeNi HEA in 1 mol/L H₂SO₄ solution. Fascinatingly, the obtuse current and dimensional obtuse current exhibit decrease first and then increase for the tendency accompanied with the increase of Al content.更多还原