アルミニウム合金のパルスレーザー誘起プルームの分光学的特性

抄録

The present paper describes spectroscopic characteristics of plume induced in the pulsed YAG laser welding of alloys containing a large amount of volatile elements. The authors have conducted the spectroscopic analyses of laser induced Al-Mg alloys plume in the air and argon atmosphere. In the air environment, the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn, and singly ionized Mg lines, as well as the intense molecular spectra of AlO and MgO formed by chemical reactions of evaporated Al and Mg atoms from the pool surface with oxygen in the air. In argon atmosphere, MgO and AlO spectra vanished, but AlH spectrum was detected. The hydrogen source was presumably hydrogen dissolved in the base metals, water adsorbed on the surface oxide layer, or H₂ and H₂O in the shielding gas. The resonant lines of Al and Mg were strongly self-absorbed, in particular, self-absorption of the Mg line was predominant. The self-absorption was stronger in the plume of higher Mg content alloys. These results show that the laser induced plume was made of metallic vapor with relatively low temperature and high density.