Development and application of integrated fiber laser and rotary friction welding technology for fabricating metal joints with superior mechanical properties
摘要
Rotary friction welding (RFW) is a solid-state joining process capable of producing high-strength joints with low energy consumption and excellent reliability. However, welding aluminum alloys remains challenging because of their high thermal conductivity and rapid heat dissipation, which can limit interfacial bonding quality. In this study, an integrated high-power fiber laser-assisted rotary friction welding system was developed to enhance the joining performance of 6061 aluminum alloy cylindrical rods with a diameter of 20 mm and a length of 40 mm. The effects of key process parameters, including feed rate, friction time, laser power, and rotational speed, were systematically investigated. The feed rate was varied from 1 to 9 mm/min, friction time from 1 to 10 s, laser power from 800 to 1200 W, and rotational speed from 1000 to 4000 rpm. The machining load increased from 3 N to 137 N as the feed rate increased from 1 to 9 mm/min, while the optimal feed rate of 3 mm/min produced a bending strength of 153.6 MPa. Increasing the friction time from 1 s to 5 s improved the bending strength from 132 MPa to 311 MPa. Laser preheating experiments demonstrated that a laser power of 1100 W provided the most stable heating performance, reaching a target temperature of 500 °C within 38 s. Under the optimized processing conditions of 1100 W laser power, 38 s preheating time, 3 mm/min feed rate, 5 s friction time, and 3000 rpm rotational speed, the welded joint achieved a maximum bending strength of 480 MPa and a peak interfacial temperature of 633.9 °C. Compared with conventional RFW, which produced a bending strength of 364.8 MPa, the proposed laser-assisted process increased joint strength by approximately 31%. Microstructural analysis confirmed enhanced interfacial plastic flow, improved metallurgical bonding, and a more homogeneous fracture morphology. This study contributes to sustainable manufacturing and energy-efficient production, supporting sustainable development goals 9 and 12 by improving manufacturing efficiency and reducing energy consumption in advanced welding.