One-dimensional steady-state model for damage by vaporization and liquid expulsion due to laser-material interaction

Abstract

A one‐dimensional steady‐state model describing the damage caused by materials removal by vaporization and liquid expulsion due to laser‐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 Mott–Smith‐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 materials‐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 high‐energy beam is negligible. Closed‐form analytical solutions are obtained and presented. The effect of heat‐source power on removal rates, vaporization rate, liquid‐expulsion rate, surface temperature, and Mach number are presented and discussed. Results are obtained for three different materials: aluminum, superalloy, and titanium.