Results of numerical simulation of pulsed laser action on metals are presented. The main feature of our model is the consideration of the movement of two phase fronts - melting and evaporation. Besides heating and melting, cooling and solidification are also taken into account, and this permits an analysis of the entire thermal cycle. One of the advantages of the present approach is the opportunity to analyze the dynamics of phase front velocities on the basis of an exact determination of the position of the phase boundaries. In the case of constant energy flux the transient periods of surface temperature, evaporation front velocity, melt thickness and their corresponding quasi-stationary values are determined. The influence of the shape of laser pulses on the dynamics of heat processes is considered. The evolution of surface temperature during pulsed laser action obtained by numerical simulation is compared with the experimental results. The influence of pulse interruption on heat process dynamics, and particularly on cooling-solidification rates, is simulated. The influence of the spike structure of laser pulses, corresponding to the cases of free and periodic spiking,is analyzed as it affects the evolution of thermal processes. The two-dimensional problem of melting-solidification in pulse laser action taking into account weak surface evaporation is considered.

https://link.springer.com/content/pdf/10.1007%2F978-94-011-1990-0_10.pdf

Heat processes in pulse laser treatment of metallic materials

Citations

Heat Processes in Pulsed Laser Action