Characteristics of state change of powder particles under laser irradiation

The state of powder particles after the interaction between laser and powder particles is one of the key factors that restrict the continuous improvement of laser coaxial powder feeding process. Using high speed photography of the shadow enhanced transient image, the change rule of the powder particle state with time under laser irradiation was clearly obtained. The dynamic model of the powder particle flight under laser irradiation was constructed, and the evolution rule of different state characteristic particles in the laser powder interaction zone was systematically studied. The results showed that the more 70% of the powder particles in the laser powder interaction zone were irradiated by laser, and the recoil force generated by the instantaneous vaporization of the particle surface under intense laser irradiation was the reason for changing the movement track and speed of the powder particles. There is a mapping relationship between particle motion acceleration and the length of “comet tail” under laser irradiation. The longer the “comet tail” length, the greater the particle motion acceleration. The brightness information of powder particles can qualitatively characterize the state of powder particles under laser irradiation.