Diagnostics of powder particle parameters under laser radiation in direct material deposition

Abstract

A comparative analysis is presented for the particle velocity and temperature in the light field of a continuous wave (CW) or pulsed CO2-laser in a coaxial jet gas flow. The problems of measuring the particle velocity and temperature in the light field are solved using noncontact registration methods based on a spectrometer and a combination of laser and optical devices. Alumina, molybdenum, nickel and aluminum powders are used with standard size distributions of the particles. It is shown that, in the field of laser radiation, powder particles get an extra acceleration due to the reactive force resulting from the recoil pressure in evaporation from particles. Laser radiation essentially influences the in-flight velocity of particle velocity and temperature.