低温水冷下AZ80镁合金表面激光熔覆Al_(63)Cu_(27)Zn_(10)涂层的组织与性能

Microstructure and Properties of Al_(63)Cu_(27)Zn_(10) Coating Prepared by Laser Cladding on AZ80 Magnesium Alloy under Low-Temperature Water Cooling Condition

为提高AZ80镁合金的表面性能,在低温流水冷却条件下采用预置粉末激光熔覆法在镁合金表面制备Al63Cu27Zn10（原子数分数,%）涂层。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、显微硬度仪、摩擦磨损试验机、电化学工作站对熔覆层和基体的微观组织与性能进行了表征和分析。结果表明：熔覆层组织均匀致密,与基体呈良好冶金结合,熔覆层主要由α-Mg,二元相Al17Mg12、Al Mg、Al3Mg2,三元相Mg32Al47Cu7、Al Mg2Zn、Mg Al2O4和非晶相组成。熔覆层的显微硬度为375~683 HV,是基体（92 HV）的4~7倍,熔覆层相对耐磨性为基体的3.2倍,电极电位提高了389.5 m V,腐蚀电流降低了两个数量级。经激光熔覆Al63Cu27Zn10（原子数分数,%）涂层后,AZ80镁合金基体的耐磨耐蚀性能得到较大改善。

To improve the surface properties of AZ80 magnesium alloy, the laser cladding of the preplaced Al63Cu27Zn10（atomis fraction, %） powder on magnesium alloy is carried out under low-temperature water cooling condition. The microstructure and properties of the coating are characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM） equipped with energy dispersive spectrometer（EDS）, microhardness tester, abrasion tester and electrochemical workstation. The results show that the cladding layers are well bonded with the substrate and are composed of α-Mg, binary phases Al17Mg12, Al Mg, Al3Mg2, ternary phases Mg32Al47Cu7, Al Mg2 Zn, Mg Al2O4 and amorphous phase. The microhardness of the cladding layer ranges from 375 to 683 HV,which is 4~7 times higher than that of the AZ80 substrate（92 HV）. The relative wear resistance of the cladding layer is 3.2 times than that of the substrate. The corrosion potential（Ecorr） is increased with 389.5 m V and the corrosion current is decreased by two orders of magnitude. After the laser cladding Al63Cu27Zn10（atomic fraction, %） layer, both wear resistance and corrosion resistance of the AZ80 substrate are greatly improved.