STUDY INTO EVAPORATION FRONT VELOCITY OF STAINLESS-STEEL DUE TO ND-YAG PULSED-LASER RADIATION

Vapor phase formation and vapor front velocity are the important features of the laser-material interaction, since material removal rate is very much related to these processes. In addition, once the vapor phase is formed, it absorbs a portion of the incident beam resulting in a temperature increase. Eventually a sufficient quantity of vapor is produced blocking the incident beam partially reaching the surface and leading to a reduction in vapor production rate. However, process reverses once the vapor expands rapidly due to pressure differential exists with its surroundings. Therefore, it becomes necessary to investigate the formation and behavior of the vapor front. Consequently, in the present study. Fourier and electron-kinetic theories are employed to compute the surface temperature and vapor front velocities due to practical laser pulse. The work is extended to include experimental measurement of the evaporation front velocities using streak photography technique. It is found that vapor velocities resulted from both theoretical approaches and the experiment are in good agreement.