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采用激光功率计、光束光斑质量诊断仪及高速摄像仪,对比研究了CO2激光及YAG激光与直流TIG电弧垂直相互作用时的光束特性和电弧特性。结果表明,CO2激光穿过TIG电弧后,激光功率显著衰减,光束散焦,能量分布状态严重劣化,而且电弧电压降低,体积膨胀,甚至产生激光支持的燃烧波;而对于Yb∶YAG激光,电弧基本不吸收激光能量,电弧对激光特性的影响可以忽略,同时电弧电压及电弧形态也没有明显变化。试验条件下,计算得TIG电弧对CO2激光和YAG激光的逆韧致吸收系数分别为14.14～26.29 m-1和1.1～2.03 m-1。同时,TIG电弧对CO2激光和YAG激光的折射率分别为0.99249～0.99454和0.99992～0.99994。TIG电弧对CO2激光的逆韧致吸收系数远高于对YAG激光的吸收率,同时,TIG电弧对YAG激光的折射率与大气相比较差异很小。这是CO2激光及YAG激光激光与电弧相互作用存在很大差异的根本原因。
A laser power meter, a beam spot quality diagnostic instrument and a high-speed camera were used to study the beam characteristics and arc characteristics of CO2 laser and YAG laser when they perpendicularly interact with DC TIG arc. The results show that the laser power decays significantly after the CO2 laser passes through the TIG arc, the beam is defocused, the energy distribution is severely deteriorated, the arc voltage is reduced, the volume is expanded, and even the laser-supported combustion wave is generated. For the Yb: YAG laser, The basic does not absorb laser energy, the impact of the arc on the laser characteristics can be ignored, while the arc voltage and arc morphology did not change significantly. Under the experimental conditions, the inverse dutile absorption coefficients of TIG arcs calculated for CO2 and YAG lasers are 14.14-26.29 m-1 and 1.1-2.03 m-1, respectively. At the same time, the refractive index of TIG arc to CO2 laser and YAG laser are 0.99249 ~ 0.99454 and 0.99992 ~ 0.99994, respectively. Inverse Toughness absorption coefficient of TIG arc to CO2 laser is far higher than that of YAG laser. Meanwhile, the refractive index of TIG arc to YAG laser is less than that of atmospheric gas. This is the fundamental reason that there is a big difference between CO2 laser and YAG laser and arc interaction.