Abstract The Al2CoCrCuFeNiTix high-entropy alloy coatings were prepared by laser cladding on Q235 steel surface. The microstructure, hardness and corrosion resistance were investigated by means of scanning electron microscopy with spectroscopy (SEM/EDS), transmission electron microscopy (TEM), micro/Vickers hardness tester and electrochemical workstation. Experimental results show that the cladding coating consists of cladding zone (CZ), bounding zone (BZ) and heat affected zone (HAZ). Al2CoCrCuFeNiTix high-entropy alloy coating was mainly composed of equiaxed grain; the distribution of chemical compositions is uniform. Alloy coating exhibited high hardness due to solid solution hardening and dispersion strengthening effect, the highest surface hardness of 988 HV, about 4.5 times as much as the substrate; the passivation film on Al2CoCrCuFeNiTix high-entropy alloy coating surface made the alloy have excellent corrosion resistance in 0.5 mol/L H2SO4 solution, the alloy coatings were appearing repassivation except Ti1.0 alloy coating. The coating have good corrosion resistance in 3.5% NaCl solution because Ti elements can maintain a stable state of purification. Circular polarization curves show that the Al2CoCrCuFeNiTix high-entropy alloy coating does not appear pitting in 0.5 mol/L H2SO4 and 3.5% NaCl solutions.

中文翻译：

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快速凝固制备的Al 2 CoCrCuFeNiTi x 高熵合金涂层的组织、硬度和耐蚀性

摘要 采用激光熔覆在Q235钢表面制备Al2CoCrCuFeNiTix高熵合金涂层。采用扫描电子显微镜（SEM/EDS）、透射电子显微镜（TEM）、显微/维氏硬度计和电化学工作站对显微组织、硬度和耐腐蚀性能进行了研究。实验结果表明，熔覆层由熔覆区（CZ）、边界区（BZ）和热影响区（HAZ）组成。Al2CoCrCuFeNiTix 高熵合金涂层主要由等轴晶组成；化学成分分布均匀。合金涂层由于固溶硬化和弥散强化作用表现出高硬度，最高表面硬度为988 HV，约为基体的4.5倍；Al2CoCrCuFeNiTix 高熵合金镀层表面的钝化膜使合金在0.5 mol/L H2SO4 溶液中具有优异的耐蚀性，除Ti1.0 合金镀层外，合金镀层均出现再钝化。该涂层在3.5% NaCl溶液中具有良好的耐腐蚀性，因为Ti元素可以保持稳定的净化状态。圆极化曲线表明，Al2CoCrCuFeNiTix 高熵合金涂层在0.5 mol/L H2SO4 和3.5% NaCl 溶液中未出现点蚀。