采用IPG YLS-6000光纤激光器焊接4 mm厚5083-H116铝合金板，研究了焊接工艺参数对焊缝成形及缺陷的影响规律，分析了接头显微组织及力学性能。研究结果表明，激光功率、焊接速度及离焦量三者的匹配综合影响焊缝的熔透情况；光纤激光焊接5083铝合金的主要问题是表面下凹及咬边；在熔透条件下采用较高功率5 kW及6 kW，速度范围在6 m/min~9 m/min的光纤激光能够得到较为理想的焊缝；在零离焦、功率6 kW及焊接速度9 m/min的优化参数下，焊接接头中从熔合线至焊缝中心, 结晶形态从细密的柱状晶逐渐转变为等轴树枝晶，并存在较明显的成分偏析；硬度测试表明焊缝区显微硬度存在波动，其平均值低于母材；接头抗拉强度为287 MPa，约为母材的83.9%，屈服强度为227 MPa，延伸率为3.57%，断裂位置位于焊缝区，断裂类型属韧性断裂。

Welding of 5083-H116 aluminum plate with thickness of 4 mm using IPG YLS-6000 fiber laser is presented. The influence of parameters on the weld forming and weld defects is carried out in this paper. Also, microstructure and mechanical properties of joint is analyzed. It indicates that laser power, speed and defocus have great effects on penetration state. The main problems of weld of 5083-H116 aluminum plate are sag and undercut. Under the condition of penetration, using high power of 5 kW and 6 kW and speed range from 6 m/min to 9 m/min can get ideal weld formation. With the optimal parameters of zero defocus, 6 kW power and 9 m/min welding speed, metallographic observations indicate that crystalline morphology near the fusion line is dense columnar, and in center of the weld which is isometric dendrite. Besides, the segregation of weld is more visible. The test shows that the micro-hardness of weld fluctuates and the mean value is less than the parent material. Tensile strength of joint is up to 287 MPa, about 83.9% of parent material. Yield strength is about 227 MPa. Elongation is about 3.57%. The tensile fracture happens in weld, and belongs to ductile fracture.