STUDY OF THERMAL-BEHAVIOR AND FLUID-FLOW DURING LASER-SURFACE HEATINGOF ALLOYS

Transient and steady state laser melting problems are numerically simu lated for steel and Al-4.5% Cu. Enthalpy and apparent capacity methods are used to solve the energy equation, and the momentum equations are solved in the liquid domain and mushy zone with the SOLA-VOF algorith m. Using a laser with a top-hat profile, a wide range of studies are p erformed by varying the beam power density and the beam radius. The st reamline plots show that the flow pattern is dependent on the strength of the rotating cell along with heat flux. It is found that the shape of the pool, the surface velocity, and the surface temperature are qu ite different from those without convection in the mushy zone. Convect ion in the mushy zone plays an important role in heat transfer and flu id flow during laser melting.