激光熔覆Ni-WC陶瓷颗粒增强高熵合金涂层组织与性能

Microstructure and properties of laser cladding Ni-WC ceramic particle reinforced high-entropy alloy coating

采用激光熔覆技术在0Cr13Ni5Mo不锈钢表面制备Ni-WC陶瓷颗粒增强AlCoCrFeNi高熵合金涂层,运用扫描电镜、X射线衍射仪与显微硬度计分析表征复合涂层微观组织、物相和显微硬度,应用摩擦磨损试验和电化学腐蚀试验研究Ni-WC陶瓷颗粒含量对磨损和腐蚀性能的影响。以显微硬度和稀释率为指标,设计三因素三水平正交试验,确定单道最佳熔覆工艺为:激光功率1600 W、扫描速度6 mm·s^(-1)、送粉速度1.4 r·min^(-1);使用该最佳工艺,选择50%搭接率,分别制备不同质量分数Ni-WC颗粒增强AlCoCrFeNi高熵合金复合涂层;对样品涂层进行组织表征和性能测试。结果表明:涂层均为体心立方晶格相;随着Ni-WC质量分数增加,涂层显微硬度增加,当Ni-WC质量分数为5%时,涂层平均显微硬度值为587 HV 0.3,约为基体的1.69倍;随着Ni-WC质量分数增加,涂层的耐磨损和耐腐蚀性能先增后减,当Ni-WC质量分数为3%时,复合涂层磨损率最低,为5.7×10^(-5) mm^(3)·N^(-1)·m^(-1),同时自腐蚀电流密度最小,为1.22×10^(-6) A·cm^(-2),呈现出优异的耐磨损和耐腐蚀性能。

Ni-WC ceramic particles reinforced AlCoCrFeNi high-entropy alloy coating is prepared on the surface of 0Cr13Ni5Mo stainless steel by laser cladding technology.X-ray diffraction,scanning electron microscopy,microhardness tester and other methods are used to analyze and characterize the microstructure,phase,and microhardness of the coating.Friction and wear tests as well as electrochemical corrosion tests are applied to study the effect of Ni-WC ceramic particle content on wear and corrosion performance.Using microhardness and dilution rate as the indexes,orthogonal experiments with three factors and three levels are designed to determine the optimal single-pass cladding parameters as follows:laser power 1600 W,scanning speed 6 mm·s-1,powder feeding speed 1.4 r·min^(-1).AlCoCrFeNi composite coatings with different mass fractions of Ni-WC particles are prepared using the above-mentioned optimal process parameters and 50%overlapping ratio.Then microstructural characterization and performance testing of the sample coating are conducted.All coatings have the BCC phase.With the increase of Ni-WC content,the microhardness of the coating increases.When the mass fraction of Ni-WC is 5%,the average microhardness value of the coating is 587 HV 0.3,which is about 1.69 times that of the substrate.However,with the increase of Ni-WC content,the wear resistance and corrosion resistance of the composite coating firstly increase and then weaken.When the mass fraction of Ni-WC is 3%,the composite coating has the lowest wear rate 5.7×10^(-5) mm 3·N^(-1)·m^(-1) and the minimum self-corrosion current density 1.22×10^(-6) A·cm^(-2),showing excellent wear resistance and corrosion resistance.