A one-dimensional unsteady-state heat transfer model based on explicit finite difference method of solution has been developed to simulate the thermal profile in the course of laser surface alloying of a Cr-deposited Cu substrate with a continuous-wave CO 2 laser. In this model, a suitable temperature/phase dependence of the material properties has been considered. The temperature profile and depth of melting are found to be strong functions of the incident power density and interaction time. The mechanism of transient melting and solidification following laser irradiation is discussed in the light of the present model