A Review of Meso-micro Modeling and Simulation Methods of Selective Laser Melting Process

The selective laser melting（SLM） process is a complex physical and chemical metallurgical process, which not only involves multi-scale issues such as macro part-scale, meso molten-pool-scale and micro metallographic-scale but also includes multi-physical behaviors such as phase change, fluid flow, heat transfer and mass transfer. Using experimental methods to directly observe the phenomenon online is not only extremely difficult but also of a long period and high cost. Therefore, a high-fidelity numerical simulation method has become an important means to reveal the mechanism of the SLM process and predict the forming quality. This study focused on the two aspects of mesoscopic powder molten pool evolution（powder laying, molten pool evolution kinetics） and microscopic solidification structure formation（crystal nucleation, dendrite growth） and discussed the modeling and simulation methods of the SLM process in detail. The features, advantages and applicability of the physical models and simulation methods were analyzed, and the simulation and application statuses of the mesoscopic molten pool and microstructure morphology of the SLM process were summarized. This review was ended up with the perspectives of the challenges and developments of the meso-micro numerical simulation technology for the SLM process.