Modeling Exposure of Additively Manufactured Metallic Materials to Laser Pulses of Complex Temporal Shape

The results of studying the impact of laser pulses with different temporal shapes on a metallic material (structural steel) produced by selective laser melting are reported for the first time. The influence of the conventional and complex temporal shapes of laser pulses with identical energies and durations on initiation of dominant material destruction mechanisms and the effect of recoil pressure are investigated using mathematical modeling. The model allows for the nonlinear depth distribution of porosity characteristic of additive metallic materials. It is shown that pulses of complex temporal shape, which combine a long high-energy pulse and a short high-intensity pulse, cause an increase in the recoil pressure much higher than the increase in the capillary pressure. The increase in the recoil pressure in the laser interaction zone initiates an increase in the volume of the removed material and increases the laser processing speed in additive manufacturing of items. The results demonstrate the potential of using laser pulses of complex temporal shape for postprocessing of metallic materials produced on the basis of additive technologies.