激光选区熔化增材制造中金属蒸气与飞溅相互作用研究  

Investigation of Interaction between Vapor Plume and Spatter During Selective Laser Melting Additive Manufacturing

作　　者：殷杰 郝亮[1,2] 杨亮亮[3] 李妍 李正 孙庆磊[1,2] 石斌 Yin Jie;Hao Liang;Yang Liangliang;Li Yan;Li Zheng;Sun Qinglei;Shi Bin(Gemological Institute,China University of Geosciences,Wuhan 430074,Hubei,China;Advanced Manufacturing Research Institute,China University of Geosciences,Wuhan 430074,Hubei,China;Wuhan National Laboratory for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China)

机构地区：[1]中国地质大学(武汉)珠宝学院,湖北武汉430074 [2]中国地质大学(武汉)先进制造研究所,湖北武汉430074 [3]华中科技大学武汉光电国家研究中心,湖北武汉430074

出　　处：《中国激光》2022年第14期100-111,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(61805095,51675496,51902295);湖北省揭榜制科技项目(2021BEC010);武汉市科技局项目(2020010601012172);中央高校基本科研业务费专项资金资助项目。

摘　　要：金属蒸气、飞溅和熔池是激光选区熔化(SLM)增材制造过程中的重要物理现象,与成形质量关联密切。本文基于高时空分辨原位成像系统,研究了SLM成形过程中金属蒸气与飞溅的相互作用。实验发现:金属蒸气不仅可以间接作用于粉末颗粒,即通过卷吸作用诱导的惰性卷吸气流形成粉末飞溅,还可以直接作用于粉末颗粒,即通过抬升力或反冲力使粉末颗粒进入蒸气羽流或落回粉床。得到了从熔池“液基”出射的熔滴飞溅以及从基板“固基”出射的粉末飞溅的速度阈值。将SLM成形过程中的飞溅作为示踪粒子,原位测量获得了蒸气反冲压。研究蒸气反冲力作用下金属蒸气与飞溅的“气-固”相互作用,为深入理解金属蒸气与熔池的“气-液”相互作用等现象奠定了基础。Objective Selective laser melting(SLM),also known as laser powder bed fusion(LPBF),has broad application prospects due to its excellent performance and high fabrication accuracy.SLM technology is developing toward multibeam,multi-material,high quality,and high-efficiency manufacturing.However,defects,such as internal metallurgical defects,and residual stress,restrict its process reliability and repeatability.Investigating the laser-matter interaction and its internal relationship with forming defects is expected to provide a scientific theoretical basis for SLM to achieve stable forming with fewer defects.This work studies the interaction between vapor plume and spatter behavior during SLM based on high spatial-temporal resolution in situ imaging systems.Methods The high spatial-temporal resolution in situ imaging system consists of a high-speed video camera(Phantom 2012,Vision Research,USA),a synchronized pulsed high-power diode laser light source(CAVILUX HF,Cavitar,Finland),and a zoom lens system(12X Zoom,Navitar,USA).In this work,imaging was performed at up to 105 frames/s with a 1μs exposure time.In front of the camera lens,a Thorlabs narrow bandpass filter with a wavelength of 808 nm was placed.With a full field of view of 2.0 mm×1.8 mm,the camera setup angle between the object plane and processing plane was 45°.The spattering trajectory is the projection on the plane parallel to the CMOS detector.An image filtering algorithm used to increase the sharpness of the spatter imaging.The sizes,numbers,ejection angles,and ejection velocities of the spatter trajectory were quantified using Image J1.53.Results and Discussions(1)Droplet spatter(ejected from the“liquid base”of the molten pool)driven by the metal vapor recoil pressure.When the laser energy density is 27.5 J.mm^(-3),the ejection of the liquid column in the molten pool is not noticeable.As the laser energy density increases to 59.0 J.mm^(-3),the protrusion and the droplet column are formed at the rear of the molten pool.The super-threshold ejectio

关 键 词：激光技术 激光选区熔化 金属蒸气 飞溅 动力学 相互作用 增材制造 

分 类 号：TN249[电子电信—物理电子学]