Numerical and experimental study of the temperature field evolution of Mg alloy during high power diode laser surface melting

During the laser surface melting (LSM) of AZ31B Mg alloy, obtaining desired temperature field distribution is essential for production goal and reliable service performance. In this study, a 3D finite element model was developed to analyze the thermal characteristics during the diode laser surface melting of Mg alloy with different process parameters. The simulation visually predicts the great temperature gradient and fast cooling speed during LSM. The microstructure of the fusion zone was observed to validate the accuracy of the simulation. Verification experiment based on infrared temperature measurement (ITM) was applied. By comparing the maximum temperature values, the average heating and cooling rate and the dimension of the melt pool with various laser powers and scanning speed, the simulation results are in good agreement with the experimental measurements.