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为研究激光表面微凹坑对AZ31B镁合金耐腐蚀性能的影响,利用光纤激光器在材料表面制备微凹坑阵列。通过扫描显微镜观测微凹坑的形貌、直径和深度,利用双单元电化学工作站测试微凹坑制备前后材料表面的动电位极化曲线。结果表明:微凹坑的直径和深度均随激光功率的增大而增大,微凹坑周围出现烧蚀现象;微凹坑直径与扫描次数无显著相关性,但微凹坑圆度与扫描次数呈正相关性。在相同微凹坑密度下,与未处理试样相比,激光功率为6、10、16 W时试样的自腐蚀电位分别向正移-33、40、26 m V,自腐蚀电流分别减少了91.93%、92.09%、91.19%。激光功率为10 W时具有最好的抗腐蚀性能;在相同激光功率下,与未处理试样相比,微凹坑密度为1.5%、2.5%、5.0%时试样的自腐蚀电位分别向正移21、40、56 m V,自腐蚀电流分别减少了92.22%、92.09%、94.05%。在实验密度范围内,微凹坑密度越高,AZ31B镁合金表面的抗腐蚀性能越好。
In order to study the effect of laser dimple on the corrosion resistance of AZ31B magnesium alloy, a micro-dimple array was prepared on the surface of the material by using a fiber laser. The morphology, diameter and depth of the micro-pits were observed with a scanning microscope. The potentiodynamic polarization curve of the surface of the material before and after the preparation of the micro-pits was tested by a dual-cell electrochemical workstation. The results show that the diameter and depth of the micro-pits increase with the increase of the laser power, and ablation occurs around the micro-pits. There is no significant correlation between the micro-pits diameter and the number of times of scanning. However, The number of positive correlation. At the same micro-pit density, compared with the untreated samples, the self-corrosion potentials of the samples were positively shifted to -33,40 and 26 mV when the laser power was 6, 10 and 16 W, respectively, and the self-corrosion current decreased 91.93%, 92.09%, 91.19%. When the laser power is 10 W, the corrosion resistance is the best. At the same laser power, the self-corrosion potentials of the samples are 1.5%, 2.5% and 5.0%, respectively, compared with the untreated samples Positive shift 21,40,56 mV, self-corrosion current decreased by 92.22%, 92.09%, 94.05%. In the experimental density range, the higher the density of dimples, the better the corrosion resistance of AZ31B magnesium alloy.