Onehyphen;dimensional steadyhyphen;state model for damage by vaporization and liquid expulsion due to laserhyphen;material interaction

摘要

A onehyphen;dimensional steadyhyphen;state model describing the damage caused by materials removal by vaporization and liquid expulsion due to laserhyphen;material interaction is developed and presented. When vaporization occurs, there exists a discontinuity across the Knudsen layer of a few molecular mean free paths. This discontinuity is modeled by a Mottndash;Smithhyphen;type solution. The vaporization process creates a recoil pressure that pushes the vapor away from the target and expels the liquid. The materials are, therefore, removed in both vapor and liquid phases. The materialshyphen;removal rates are incorporated in the moving boundary immobilization transformation. The vapor phase is assumed to be optically thin so that its absorption of the highhyphen;energy beam is negligible. Closedhyphen;form analytical solutions are obtained and presented. The effect of heathyphen;source power on removal rates, vaporization rate, liquidhyphen;expulsion rate, surface temperature, and Mach number are presented and discussed. Results are obtained for three different materials: aluminum, superalloy, and titanium.