Laser pulse heating and phase changes in the irradiated region: Temperature-dependent thermal properties case

Laser heating and phase change processes in the substrate material are formulated using the energy method. Constant and temperature-dependent thermal properties (variable thermal properties) of the substrate material are considered in the simulations for comparison. Temperature rise in the substrate material and mushy zones formed across liquid-solid and liquid-vapor phases are predicted for constant and variable thermal properties cases. Laser pulse intensity resembling the actual laser pulse is accommodated in the analysis. The recession velocity predicted from the present simulation is compared with the results of analytical solution obtained previously for constant properties case. The cavity depth predicted is compared with the experimental results. It is found that the simulation for constant properties results in early evaporation of the surface and deeper cavities as compared to variable thermal properties case. The prediction of cavity depth for variable thermal properties case agrees well with the experimental results. (C) 2008 Elsevier Masson SAS. All rights reserved.