3-DIMENSIONAL ELECTRON-KINETIC THEORY APPROACH FOR LASER-HEATING - MOVING HEAT-SOURCE CONSIDERATION

Lasers are extensively used for the heat treatment of engineering surf aces. The simulation of laser heating may enhance the understanding of the process parameters and yields insight into the phenomena occurrin g within the region activated by the laser beam. Consequently, in the present study, electron-kinetic theory approach is introduced to model the three-dimensional laser heating process. However, the phase chang e (melting) process is not considered in the present study due to the fact that the temperature of the heated surface is usually kept below the melting temperature of the substrate in most surface treatment pro cesses. Since the energy equation derived is in the form of an integro -differential equation, a numerical scheme using finite-difference app roximation is employed. A laser beam with a constant velocity is consi dered as scanning the workpiece surface. The study is extended to incl ude three laser beam scanning velocities, therefore, the respective te mperature fields are computed. To validate the theoretical predictions , the surface temperature measurements are carried out. It is found th at the surface temperature rises at low scanning velocities. In additi on, the surface temperatures obtained from the measurements agree with the theoretical predictions. (C) 1998 Elsevier Science B.V. All right s reserved.