不锈钢激光选区熔化单道成形表面介观模拟与实验验证  

Mesoscale Simulation and Experimental Verification of Single-track Surface Morphology in Stainless Steel Laser Powder Bed Fusion

作　　者：李岩[1,2] 刘琪 李亚杰 李聚才[1,2] 吴志生 LI Yan;LIU Qi;LI Yajie;LI Jucai;WU Zhisheng(School of Material Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Intelligent Manufacturing Industry College of Shanxi Electronic Science and Technology Institute,Shanxi Linfen 041000,China)

机构地区：[1]太原科技大学材料科学与工程学院,太原030024 [2]山西电子科技学院智能制造产业学院,山西临汾041000

出　　处：《表面技术》2024年第17期135-145,共11页Surface Technology

基　　金：山西省基础研究计划(202203021221149);山西省重点研发计划(202202150401016);山西省科技重大专项(202101120401008);山西省高等学校科技创新项目(2022L628)。

摘　　要：目的为了获得不锈钢激光选区熔化单道成形质量好的加工参数,提高成形质量。方法对于316L不锈钢材料的激光选区熔化(SLM)成形,采用离散元方法(DEM)构建颗粒随机分布的三维介观模型,采用流体体积法(VOF)动态追踪SLM成形过程熔池传热、流动和凝固等行为,该模拟考虑相变潜热、热物性参数随温度非线性变化、Marangoni效应,研究了温度梯度引起的表面张力和蒸汽反冲力等现象对熔池液态金属流动和凝固的影响,并对不同激光参数和扫描速度对熔池温度场和内部流动的影响规律进行了分析。结果当激光功率为150 W、扫描速度为400 mm/s时,激光能使不锈钢粉末充分熔化,凝固后的轨迹形貌连续光滑。通过提高激光扫描速度和降低激光功率使得热输入减小,熔道表面成形出现球化等缺陷。结论通过单道成形实验观察和分析熔池与熔道的三维尺寸与形貌,有效验证了数值模拟的正确性,较好地预测出SLM过程中的缺陷种类,为深入理解SLM过程中的复杂物理现象和优化工艺参数提供了参考。Selective Laser Melting(SLM)is a complex additive manufacturing process that involves the melting and solidification of metal powders using a high-energy laser beam.The quality of the SLM process is influenced by various parameters such as laser power,scanning speed,scanning path,and scanning spacing.Changes in these parameters can lead to common defects such as pores,spattering,cracks,surface roughness variations,and balling phenomena.These defects,in turn,can affect the microstructure,surface morphology,and mechanical properties of the manufactured parts.To enhance the quality of laser-based additive manufacturing,extensive experimentation is required to test various parameter combinations and identify suitable process parameters that minimize defect formation.However,due to the rapid and dynamic temperature variations and gradients within the small molten pool during SLM,it becomes challenging to monitor and analyze its thermodynamic behavior through experimental means.As computer technology advances,numerical simulations at the mesoscale of powder interactions offer the potential to explore the heat and mass transfer phenomena involved in the laser-powder interaction.This,in turn,aids in understanding defect formation and evolution,optimizing SLM process parameters,reducing development time,and cutting down production costs.Performing single-track simulations can significantly reduce computation time while effectively capturing the morphology of the molten pool's free surface.Therefore,the objective of this research is to explore the fundamental principles of heat transfer and fluid flow in the SLM process through simulation.This exploration aims to provide reference guidelines for adjusting practical printing parameters,such as laser power and scanning speed,during the actual printing process.This endeavor contributes to a better understanding of the physical phenomena in SLM,ultimately optimizing print quality and efficiency.For this study,316L stainless steel was chosen as the research material.A random ar

关 键 词：激光选区熔化 熔池流动 316L不锈钢 介观模拟 单道 

分 类 号：V261.8[航空宇航科学与技术—航空宇航制造工程]