焊接方法对铝合金焊接接头微弧氧化色差的影响

目的 分析铝合金焊接接头微弧氧化过程中色差产生的原因。方法 采用单激光和激光-MIG复合焊2种焊接方法焊接2A12铝合金，利用RGB值定性描述不同焊接试样的色差差异大小，采用金相、SEM和微区XRD观察2A12铝合金单激光和激光-MIG复合焊接头微弧氧化前后的组织、微观形貌和表面物相组成。结果 经微弧氧化处理后，2A12铝合单激光焊焊件的焊缝和母材之间无明显色差，2A12铝合金激光-MIG复合焊焊件的焊缝和母材之间存在明显色差，结合金相组织、表面和截面的SEM形貌以及表面EDS和XRD测试分析结果可知，成分和表面熔融物颗粒的大小不同是铝合金焊接接头微弧氧化色差形成的主要原因，焊接接头的组织对铝合金焊接接头微弧氧化色差的产生没有影响。结论 单激光焊接接头微弧氧化后的氧化色差较激光-MIG复合焊接头的小;铝合金(2A12)焊接接头产生氧化色差主要是因为焊接接头的成分和表面熔融物颗粒大小不同，而组织对色差无影响。

Effect of Welding Methods on the Color Difference of Aluminum Alloy Welded Joints in Micro Arc Oxidation

The work aims to analyze the causes of color difference during the micro arc oxidation process of aluminum alloy welded joints. Two welding methods, single laser and laser-MIG hybrid welding, were used to weld 2A12 aluminum alloy. RGB values were used to qualitatively describe the color difference of different welding samples. The microstructure and surface phase composition of 2A12 aluminum alloy welded joints by single laser and laser-MIG hybrid welding before and after MAO were observed by metallography, SEM, and micro zone XRD. There was no significant color difference between the weld seam and the base metal of the 2A12 aluminum alloy welded joint by single laser welding after MAO treatment. However, there was a significant color difference between the weld seam and the base metal of the 2A12 aluminum alloy welded joint by laser MIG hybrid welding after MAO treatment. Based on the observation of metallographic structure, surface and cross-sectional SEM morphology, as well as surface EDS and XRD testing analysis, the different composition and surface melt particle size were the main reasons for the formation of color difference of aluminum alloy welded joints in micro arc oxidation. The microstructure of the welded joints had no effect on the generation of color difference of aluminum alloy welded joints in micro arc oxidation. The oxidation color difference of single laser welded joints after MAO is slighter than that of laser MIG hybrid welded joints. The main reason for the oxidation color difference of aluminum alloy (2A12) welded joints is the difference in the composition of the welded joints and the size of the surface molten particles, while the microstructure has no effect on the color difference.