Optical diagnostics of radiation interaction with the powder stream laterally transported during laser cladding

Abstract The paper presents a case study of powder jet interaction with laser radiation under the conditions imitating laser cladding process with a lateral material feed. Optical diagnostics was used to study the motion and heating of TiC particles sized 20–40 μm. It was established that the pulsed-periodic CO2-laser radiation of power 1 kW not only leads to the heating of particles up to 3600 K and higher, but also to the acceleration of particles in the laser beam direction, and to a substantial change in their trajectories, which results in the powder plume expansion. It is shown that laser radiation can increase the maximal velocities of particles by approximately 50% (~20 m/s). An ignition of laser plasma is observed in the focusing area with the primary radiation of argon atoms lines (transport gas). The break-up process of powder particles after laser heating is observed. The effect of transport gas flow rate on the motion of powder jets is investigated including their reflection from the flat substrate. The analysis of particle heating dynamics in the laser radiation field is carried out.