HEAT-FLOW SIMULATION OF LASER REMELTING WITH EXPERIMENTAL VALIDATION

A transient three-dimensional (3-D) conduction-based heat-flow model has been developed in order to simulate the experimental processing conditions during laser surface remelting. This study concentrates on the validation of the model by comparison with data obtained from laser remelting experiments made in the eutectic alloy Al-Cu 33 wt pct over a range of traverse speeds between 0.2 and 5.0 m/s. It is shown that the simulation not only requires thermophysical data, but also a good knowledge of the laser beam process parameters. When the steady state is reached, the fusion isotherm which outlines the liquid pool yields the trace cross section and the resulting microstructure. Good agreement with experimental data is found over the range of processing speeds for the maximum melt pool dimensions, the transverse profile of the laser trace, the melt surface shape, and the resolidified microstructural spacings.