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为了进一步深入了解超高功率光纤激光深熔焊接过程中等离子体特征,试验拍摄了深熔小孔内外等离子体形态,并采用光谱仪检测分析了光纤激光致等离子体光谱信号.利用检测得到的等离子体光谱信号,计算研究了等离子体的电子温度、电子密度、电离度以及等离子体压力特征,并分析了在小孔内不同深度处及孔外等离子体的变化规律.结果表明,孔内等离子体呈现不均匀分布特征,孔外金属蒸气远多于等离子体.等离子体光谱分析显示,光纤激光致等离子体辐射出的谱线较少,即电离程度较低.进一步的计算结果同样证实了光纤激光致等离子体处于弱电离状态,但等离子体电子密度仍然处于较高水平,且等离子体瞬态压力可达到数百个大气压.
In order to further understand the characteristics of plasma during ultra-high power fiber laser deep penetration welding, the morphology of the plasma inside and outside the deep hole was photographed and the spectral signal of fiber laser induced plasma was analyzed by spectrometer.The plasma Spectrum signal, the electron temperature, electron density, ionization degree and plasma pressure characteristics of the plasma were calculated and analyzed, and the variation of the plasma at different depths and outside the pores was analyzed. The results show that the plasma in the pores presents Uneven distribution of metal vapor outside the hole much more than the plasma.Plasma spectroscopy showed that the fiber laser plasma induced radiation less lines, that is, the degree of ionization is lower.Further calculations also confirmed the fiber laser induced The plasma is in a weakly ionized state, but the plasma electron density is still at a high level and the plasma transient pressure can reach hundreds of atmospheres.