Melt pool evolution and microstructure simulation of SLM 316L based on SPH-PFM coupling model

Abstract

The study in this work fully utilized the computational advantages of various numerical methods and established a SPH-PFM coupling model for the 316 L SLM process. The temperature field, melt pool changes, and microstructure evolution of the 316 L SLM process were simulated and calculated. The correctness of the simulation results was verified through the comparison with experiments, and a calculation platform for melt pool evolution and microstructure simulation of metal material SLM process with independent intellectual property rights was developed. (1) Establish the mathematical model required for the dynamic simulation of the molten pool in the metal material SLM process based on the SPH method. (2) Extract the temperature field data and molten pool shape from the calculation results based on the SPH method, and then substitute them into the phase field model for molten pool modeling. The formation mechanism of the microstructure morphology inside the molten pool and the micro-segregation mechanism of solute elements at different positions during solidification were analyzed and discussed. The article compared the simulation results with the experimental results. The simulation results showed good consistency with the experimental results in terms of primary dendrite spacing, secondary dendrite spacing, and melt pool microstructure morphology, proving the correctness of the model established in this article. At the same time, the SPH-PFM coupling model established in this article can effectively solve the problem of predicting the microstructure of the melt pool in the SLM process, providing a new method for the study of microstructure prediction in the SLM process.

Keywords

• Smoothed particle hydrodynamics (SPH)
• Phase field method (PFM)
• Selective laser melting (SLM)
• 316L stainless steel