(1. 哈尔滨工业大学(威海) 山东省特种焊接技术重点实验室，威海 264209；
2. 山东奥太电气有限公司，济南 250101；
3. 中车长春轨道客车股份有限公司，长春 130062)
摘 要: 采用激光填丝熔钎焊方法对5052铝合金和H62黄铜异种金属进行对接试验，填充材料为Zn-15%Al (质量分数)药芯焊丝，研究激光功率对接头微观组织、界面层结构和力学性能的影响。结果表明：当激光功率2100 W时，接头因热输入过低而发生断裂，激光功率在2400~3300 W范围时，获得了性能良好的接头。黄铜侧界面附近的过渡区有Al4.2Cu3.2Zn0.7( 相)和CuZn5化合物生成，界面层结构可分为连续的CuZn相层和锯齿状的 相层，且随着激光功率增大，CuZn界面层的厚度随之增大。界面层附近出现显微硬度最大值，焊缝区显微硬度大于母材。随着激光功率的增加，接头的拉伸强度先增大后减小，当激光功率为2700 W时，原始接头和磨平余高后接头的拉伸强度最大，分别为128 MPa和104 MPa。焊缝位置断口为准解理断裂，界面层位置断口为解理断裂。
关键字: 激光熔钎焊；铝/黄铜异种金属；微观组织；界面层结构；力学性能
（1. Harbin Institute of Technology at Weihai, Shandong Provincial Key Laboratory of Special Welding Technology, Weihai 264209, China;
2. Shandong Aotai Electric Co., Ltd., Jinan 250101, China;
3. CRRC Changchun Railway Vehicles Co., Ltd., Changchun 130062, China）
Abstract:The laser welding-brazing process was developed for joining 5052 aluminum alloy and H62 brass in butt configuration with Zn-15%Al filler. The influences of laser power on the microstructure, interface layer structure and mechanical properties of the joints were studied. The results show that the joints breaks due to the low heat input with the laser power of 2100 W and acceptable joints are produced at the laser power of 2400-3300 W. The interfacial microstructure mainly consists of serrated layer Al4.2Cu3.2Zn0.7 adjacent to the weld seam and a straight continuous layer CuZn close to the brass substrate. The thickness of CuZn phase increases with the laser power increasing. The micro-hardness in the weld seam is greater than that in the base metal and the maximum value appears near the interface at the brass side. The tensile strength of joints increases first, and then decreases with the increase of the laser power, and the highest tensile strength of the original joints is 128 MPa and the joint of reinforcement-flattened is 104 MPa obtained at laser power of 2700 W. The fractography of weld seam is characterized by quasi-cleavage fracture, while the cleavage fracture is observed for the interfacial layer.
Key words: laser welding-brazing; Al/brass dissimilar metals; microstructure; interface structures; mechanical properties
