Thermohydrodynamics analysis of molten pool in laser texturing and laser welding

Some experiments of laser texturing for magnetic memory disks were carried out in order to estimate the effect of evaporation to bump formation. Considering the experimental results, a mathematical model based on thermohydrodynamics was established to analyze fusion phenomena accompanied with evaporation. Latent heat of vaporization, movement of gas and liquid interface accompanied with evaporation, evaporation recoil force and surface tension caused by temperature gradient were considered. VOF method was applied to numerical computations of the free surface problem. Some numerical examples were calculated and bump formation process was discussed. As the results, it was made clear that quantity of evaporation is a little, but surface geometry of molten metal is influenced by movement of gas and liquid interface accompanied with evaporation greatly in addition to effect of flow of liquid metal in the molten pool.