关键词: 水导激光, 碳纤维增强聚合物, 几何形貌, 损伤机理

Abstract: After water jet guided laser machining, CFRP exhibited thermal damages on the cut groove surfaces and cross-sections, which was an important factor affecting the materials mechanics properties and reducing the service performance. To address these issues, the influences of machining parameters on the geometric and surface morphology of grooves were analyzed, and the formation mechanism of surface and cross-sectional thermal damages was investigated herein. The results indicate that high laser power, low pulse frequency, and low cutting speed may effectively increase the depth of the grooves. The interaction between the laser and the material, as well as the flushing action of the water jet, are the main reasons for the formation of thermal damages on the groove surface. In the cutting experiment of 2 mm thick CFRP, it is found that the width of the heat affected zones in the cross-sections is related to the arrangement of the fibers. The heat affected zone width is the largest for 0° carbon fibers, followed by 45° and 135° carbon fibers, which have similar widths, and the width is the smallest for 90° carbon fibers. In addition, increasing the water jet velocity is beneficial for suppressing the expansion of the thermal affected zones. When the water jet velocity is increased from 80 m/s to 120 m/s, the maximum width of the thermal affected zones decreases by 35.7%.

Key words: water jet guided laser, carbon fiber reinforced polymer(CFRP), geometric morphology, damage mechanism