近红外光纤激光与蓝光半导体激光焊接紫铜工艺对比研究

目的 提高紫铜激光焊接接头的力学性能，并分析激光工艺参数对焊缝外观及焊缝微观组织的影响规律。方法 分别对蓝光半导体激光与近红外光纤激光焊接紫铜的工艺参数进行优化设计，采用光学显微镜观察焊缝的外观形貌，采用拉力机测试焊缝的抗拉强度，采用金相显微镜观察和分析焊缝的微观组织。结果 当采用近红外光纤激光进行焊接时，功率为2 000 W，焊接速度为20 mm/s，焊缝抗拉强度为156 MPa。当采用蓝光半导体激光进行焊接时，功率为500 W，焊接速度为20 mm/s，焊缝抗拉强度为246 MPa，达到母材抗拉强度的80%。结论 由于铜对蓝光波长的吸收率较高，当采用蓝光半导体激光进行焊接时，热量输入较低，焊缝的变形相对较小，并且焊缝中心各个方向上的温度梯度相同，容易形成等轴晶，有利于力学性能的提高。

Comparative Study on Welding Process of Red Copper with Blue Diode Laser and Near Infrared Fiber Laser

The work aims to improve the mechanical properties of red copper laser welded joint, and analyze the effects of laser process parameters on appearance and microstructure of weld. The process parameters of welding red copper by blue diode laser and near infrared fiber laser were optimized. The appearance of the weld was tested by microscope, the tensile strength of the weld was tested by tensile machine, and the microstructure of the weld was tested by metallographic microscope. When welding with near infrared laser, the power was 2 000 W, the welding speed was 20 mm/s, and the tensile strength of weld was 156 MPa. When welding with diode laser, the power was 500 W, the welding speed was 20 mm/s, and the tensile strength of weld was 246 MPa, reaching 80% of the tensile strength of the base metal. Due to the high absorption rate of copper to blue ray wavelength, when welding with blue diode laser, the overall heat input is low, the deformation of weld was low relatively, and the temperature gradient in each direction of the weld center is the same, which is likely to form equiaxed crystals. It is conducive to the improvement of mechanical properties.