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用化学复合镀技术在45钢基体上制备NiAl/Al2O3复合镀层,并用高功率连续CO2激光在多种扫描速度及功率密度下对镀层进行强化。采用光学显微镜(OM)、能谱(EDS)、扫描电子显微镜(SEM)、X射线(XRD)和显微硬度仪(载荷200 g、加载时间15 s)分别对镀层强化前后表面及截面形貌、元素、物相、显微硬度等进行分析。结果表明:用高功率、快扫描、大光斑的工艺直接合成了Ni30Al20Fe金属间化合物,并制备出无裂纹和气孔,连续完全致密,与基体形成冶金结合的涂层,截面由表及里可分为4层:激光作用层、过渡层、热影响区(HAZ)以及基体,Al2O3颗粒均匀分布在过渡区,激光强化层显微硬度约是基体的4倍,这主要是由于Al2O3的弥散强化作用和强化相Ni0.77AlFe0.23、Fe0.64Ni0.36的存在共同提高了镀层的硬度。
The NiAl / Al2O3 composite coating was prepared on 45 steel substrate by chemical composite plating and the coating was strengthened by high-power continuous CO2 laser at various scanning speeds and power densities. The surface and cross-sectional morphology of the coating were investigated by OM, EDS, SEM, X-ray diffraction (XRD) and microhardness tester (load 200 g, loading time 15 s) , Elements, phase, micro-hardness analysis. The results show that the Ni30Al20Fe intermetallic compound is directly synthesized by high power, fast scanning and large speckle, and the coating with no cracks and pores, continuous and complete dense and metallurgical bond with the matrix is prepared. Is 4 layers: the laser action layer, the transition layer, the heat affected zone (HAZ) and the matrix, Al2O3 particles are uniformly distributed in the transition zone, and the laser microhardness is about 4 times that of the matrix, which is mainly due to the dispersion strengthening effect of Al2O3 And strengthen the presence of Ni0.77AlFe0.23, Fe0.64Ni0.36 jointly improve the hardness of the coating.