【摘要】 研究了双光束行星系焊接技术在SiC_p/Al复合材料焊接中的应用，重点探讨了不同行星系参数对接头焊缝成形、熔合区微观结构及力学性能的影响，并与单激光直线焊接进行对比，分析其显微组织演变。结果表明，125 Hz的搅拌频率和0.9～1.2 mm的搅拌直径能够显著提升焊后表面的对称性，改善表面成形质量。行星系焊接通过双光束和搅拌作用，有效降低了热输入集中度，抑制了Al₄C₃相的生成和长大，优化了焊缝微观结构，显著提高了焊接接头的强度。试验结果显示，行星系焊接接头的最大拉伸强度达到190 MPa，为母材强度（216 MPa）的87.9%，单激光直线焊接接头强度（147 MPa）的129.3%。研究表明，行星系焊接技术在SiC_p/Al复合材料焊接中具有显著优势，为高性能复合材料的焊接提供了新的工艺路径。更多还原

【Abstract】 Objective SiC_p/Al composites have been widely used in the aerospace and electronics fields owing to their high specific strength and excellent thermal properties. However, welding such composites remains challenging because of the thermal mismatch between SiC and the aluminum matrix, which often results in interfacial reactions that generate brittle phases（e. g., Al 4 C 3）, porosity, and cracks. This study aims to address these challenges by applying a novel dual-beam planetary laser welding（PLW） method. Through comparative experiments and conventional single-beam welding, this study investigates how different planetary parameters（e. g., stirring frequency and diameter） influence weld formation, microstructure, and mechanical performance, with a focus on weld integrity optimization and minimizing defects.Methods A 2A14 aluminum alloy reinforced with 15% volume fraction SiC particles（15 μm） was used as the base material. Dualbeam welding was performed using two YMM-6000 lasers（main: 1080 nm, 50-μm core; planetary: 1050 nm, 200-μm core）. The planetary beam circled the main beam with controllable stirring diameter and frequency, creating a stirring effect in the molten pool（Fig. 2）. The welding speed was fixed at 100 mm/s, with main and planetary beam powers of 2600 W and 1300 W, respectively. Six experimental groups were formed with varying planetary parameters（Table 2）, with a single-beam linear welding sample serving as the reference. The sample’s microstructure was examined via scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS）, and electron backscatter diffraction（EBSD）. Their mechanical properties were assessed via room-temperature tensile testing, while the fracture surfaces were analyzed via SEM.Results and Discussions PLW significantly improved the weld surface morphology and structural integrity. Increasing the stirring frequency（125 Hz and 250 Hz） enhanced the weld symmetry, while the weld surface showed no signs of asymmetry or incomplete fusion. Increasing the stirring diameter from 0.6 to 1.2 mm broadened the weld width and improved the surface smoothness（Fig. 4）. The resulting weld cross-sections（Fig. 5） displayed a typical goblet-shaped profile with wider tops, indicating effective heat input redistribution. Compared to single-beam welding（Fig. 6）, PLW effectively mitigated energy concentration at the weld center and reduced pore formation. EDS and EBSD analyses revealed that the amount and size of Al4C3 phases were significantly reduced under optimal PLW conditions. It was demonstrated that the Al₄C₃ phase size decreased from 40.0 to 13.5 μm at 0.6 mm and 1.2 mm diameters, respectively. However, excessively high stirring frequencies（250 Hz） led to local overheating and crack formation at the weld top [Fig. 9（f）]. EBSD phase mapping demonstrated lower Al4C3 and SiC contents in PLW weld centers compared to single-beam welds（Fig. 11 versus Fig. 12）. The planetary process also promoted grain refinement and uniform orientation, while the kernel average misorientation（KAM） maps indicated higher dislocation density, implying enhanced dislocation strengthening. Mechanical performance results further validated the benefits of PLW. The tensile strength reached a maximum of 190 MPa under 0.9-mm diameter and 125-Hz frequency—equivalent to 87.9% of the base material strength and 129.3% of the single-beam weld strength. By contrast, the 0.6-mm diameter or 250-Hz frequency samples exhibited lower strength due to excessive Al 4 C 3 formation and defect accumulation. Fractographic analysis（Fig. 14） showed primarily brittle fractures; however, under optimal parameters, ductile features such as dimples also appeared, suggesting improved fracture resistance.Conclusions The dual-beam PLW method effectively enhanced weld formation, suppressed Al4C3 generation, and improved the microstructural uniformity and mechanical strength. The optimal parameters（diameter: 0.9 mm; frequency: 125 Hz） yielded a tensile strength of 190 MPa and avoided common welding defects such as pores and cracks. Compared with single-beam welding, PLW offers significant advantages in terms of heat distribution, grain refinement, and dislocation strengthening. These findings demonstrate that PLW provides a promising route for the high-quality welding of SiC_p/Al composites.更多还原