The Effect of Adhesive on Arc Behaviors of Laser-TIG Hybrid Weld Bonding Process of Mg to Al Alloy

The effect of adhesive on arc behaviors was investigated during the laser-TIG hybrid weld bonding process of Mg to Al alloy. The welding plasma shape, optical spectrum, current, and voltage were acquired by plasma behavior analytic system which was composed of high speed camera, optical spectrometer, digital oscilloscope, and personal computer. For comparison, the laser-TIG hybrid welding without adhesive was conducted under the same conditions. The results showed that the addition of the adhesive increased the pressure inside the laser keyhole, leading to a severe jet of metal vapor. Much more Mg atoms entered the arc plasma, ionizing instead of Ar atoms. The electron temperature of arc plasma was decreased. In contrast, the electron density of arc plasma was increased. Moreover, the arc current path was contracted by the thermal pinch effect. Further, the welding voltage was increased. Welding efficiency was increased, and the deeper penetration was obtained.