This study aimed to improve the corrosion resistance of Mg alloys, and to this end, AZ31 Mg alloy was subjected to laser surface re-melting using a fiber laser. Subsequently, a comparative analysis was conducted on the microstructures of the re-melted surfaces under various laser power settings, and the influence of laser surface re-melting on corrosion characteristics was investigated through a potentiodynamic polarization test. The test results show that laser surface re-melting produced a distinct reduction in the crystallite size of magnesium, ranging from 11.23–15.80 μm within the laser-melted layers. The maximum melted layer thickness of 820 μm was achieved with a laser power of 2100 W. The process of laser surface re-melting notably heightened the hardness, particularly as the power increased, which was attributed to swift solidification. The most noteworthy hardness measurement of 92.1 HV was recorded at 2100 W. Thus, the study shows that laser surface re-melting significantly enhances the corrosion resistance of Mg alloys, primarily owing to the formation of a corrosion product. The smaller grain size on the surface contributes to the formation of a dense product film.

中文翻译：

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激光表面改性AZ31镁合金的表面显微组织及腐蚀表征


本研究旨在提高镁合金的耐腐蚀性能，为此，利用光纤激光器对AZ31镁合金进行激光表面重熔。随后，对不同激光功率设置下重熔表面的微观结构进行了对比分析，并通过动电位极化测试研究了激光表面重熔对腐蚀特性的影响。测试结果表明，激光表面重熔使激光熔化层内的镁晶粒尺寸明显减小，范围为 11.23–15.80 μm。激光功率为 2100W 时，最大熔化层厚度达到 820 μm。激光表面重熔化过程显着提高了硬度，特别是随着功率的增加，这归因于快速凝固。最值得注意的硬度测量结果为 2100W，结果为 92.1 HV。因此，研究表明，激光表面重熔显着增强了镁合金的耐腐蚀性，这主要是由于腐蚀产物的形成。表面上较小的晶粒尺寸有助于形成致密的产品膜。