选择性激光熔化工艺的介-微观建模与仿真方法综述

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

选择性激光熔化(Selective laser melting, SLM)工艺是一个复杂的物理化学冶金过程,既涉及宏观零件尺度、介观熔池尺度和微观金相尺度等多尺度问题,又包含相变、流动、传热、传质等多物理场耦合作用。由于采用实验手段在线观测工艺过程十分困难,并且周期长、成本高,因此高保真的数值模拟方法已成为探究SLM工艺机理、预测工艺成形质量的重要手段。从介观粉末熔池演变和微观凝固组织形成两个方面,详细论述了SLM工艺数值模拟的物理模型与仿真方法的内涵,分析了各个物理模型和仿真方法的特点、优势及其适用范围,并综述了SLM工艺过程介观熔池物理行为和微观组织形貌的数值仿真研究现状。最后,总结了SLM介微观数值模拟方法目前所面临的挑战和发展趋势。

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.