Laser melting of solids—An exact solution for time intervals greater than the transit time

Abstract

The thickness of the molten layer and the rate of melting of a solid slab are obtained for time intervals greater than the transit time. Two cases are considered: one for targets with a thermally insulated rear surface and the other for targets with cooling at the rear surface. A simple suggested model for the melting process together with the integral form of the heat diffusion equation and an appropriate boundary condition at the interfacial boundary between the liquid and solid phases are used to derive the required results. Computations are carried out on a slab of aluminum of thickness l=10−3 m subjected to constant laser irradiance q0=1011 W/m2, at different values for the heat transfer coefficient at the rear surface.