Under laser pulse heating, a
non-equilibrium heat and mass transfer model based on the non-Fourier law is developed for surface
rapid melting and solidification process (RMSP) of Uniphase binary alloys.
Non-equilibrium kinetics and Aziz's continuous growth model are introduced in the model to describe the moving solid/liquid interface and to explain the departure from the interface equilibrium thermodynamics. This problem involves heat and mass diffusion with a moving boundary of solid/liquid interface and is solved by an implicit Von Neumann's difference format with second-order precision and interface tracing method. Using this model, we have analyzed laser-irradiated surface melting and solidification of dilute binary Al-Cu alloys. The calculating results show that there are very prominent effects of solid overheating and melt undercooling resulting from the high energy density of laser and interface non-equilibrium kinetics on the process. Large variations of interface velocity are. also seen during the process and depend on the substrate material and heat flux. The interface temperature, velocity, solute concentration and non-equilibrium partition coefficient varying with interface location are calculated. And the fluctuation of the interface velocity and solute concentration during the solidification is also predicted.