【摘要】 对Nd:YAG激光束与Al合金相互作用产生的光学信号进行了研究,并开发了一套可对光信号进行提取和分析的检测系统。在同一条焊缝上焊接速度保持恒定,使激光功率线性增加,检测激光焊接过程中从焊缝表面刚开始熔化到全熔透的整个过程的光学信号。利用金相显微镜和扫描电镜确定焊缝横截面的特征量。试验结果表明,焊缝横截面的特征量同光学信号具有较好的匹配关系。为激光焊接过程中的通过光学信号对焊缝成形的在线控制奠定基础。此外本文对表面熔透、表面反射率和熔池曲率对光信号的影响作了解释和分析。更多还原

【Abstract】 Optical signals generated in the interaction zone between an Nd:YAG laser beam and an aluminum alloy were investigated. A system was developed that enables such signals to be recorded and analyzed. The laser beam welding process was monitored, from the first visible signs of surface damage to full penetration of the work piece, by linearly increasing the laser power with a constant welding rate. The characteristics on transverse weld sections were established by using optical and scanning electron microscopy. The results show that the optical signals measured were consistent with well-defined characteristic modes. The effects of surface penetration, surface reflectance and weld pool curvature on the signals produced were noted and discussed.更多还原