Establishment of a three-dimensional mathematical model of SLM process based on SPH method

Abstract

The present work constructed a three-dimensional mathematical model of the selective laser melting (SLM) process based on the smoothed particle hydrodynamics (SPH) method. The Navier–Stokes equation was used to control the continuous molten metal flow; the model of continuous surface tension, the wetting effect, and Marangoni shear force were used to simulate the shape and evolution of the molten pool; the Beer–Lambert-type heat source model was used to reflect the thermal interaction between the laser and the powder bed. A rigid body motion model was employed to simulate the motion of particles in particle-reinforced materials. The accuracy of the model used was verified by the example of the square-to-circle surface tension model and the classic example of the block falling into the water. The stochastic powder bed model was used to explore the temperature field and flow field in the SLM process. The molten pool morphology and temperature under different laser powers were discussed and compared with the simulation results of temperature field through different numerical methods, which verified the accuracy of SPH method for SLM process simulation. The SLM process of metal matrix composites with TiC particles was preliminarily explored, which laid a foundation for the next step to simulate the movement of particle-reinforced materials in the molten pool formed by the SLM process.