Numerical Analysis of Melting and Evaporation Behavior of Molybdenum Layer Irradiated with a Laser Beam

Abstract

A numerical simulation using the molecular dynamics method is carried out for the study of a rapid phase change of a molybdenum layer which is strongly irradiated with a laser beam, and the atoms’ behavior near the interface between a vapor/liquid phase and a solid phase is analyzed. The laser irradiation is characterized by many energy carriers, which are absorbed or scattered by atoms. In the present model the trajectories of the energy carriers from the vapor phase to the solid phase are traced by means of the Monte-Carlo method. The vapor/liquid-solid interface is determined by a new model. The laser absorption of the solid phase layer is calculated as a function of time and a shielding effect of the vapor cloud is examined. It is the remarkable result from the analyses that the velocity distribution of the thin layer involving the interface is close to Maxwell's distribution. This shows that Maxwell's distribution can be applied to the boundary condition of the Boltzmann equation for thermal problems involving melting and evaporation due to strong heating. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.