Numerical and experimental study on keyhole and melt flow dynamics during laser welding of aluminium alloys under subatmospheric pressures

Li, Liqun; Peng, Genchen; Wang, Jiming; Gong, Jianfeng; Meng, Shenghao

doi:10.1016/j.ijheatmasstransfer.2018.12.165

Cited by 71 publications

(23 citation statements)

References 36 publications

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“…It computes the wire resistive heating, alloy melting, net vaporization and re-solidification, fluid flow, free surface deformation, and metal transfer using a Volume of Fluid (VOF) method (Hirt and Nichols, 1981) are not repeated here. Concerning the main new developments made for this study, it is assumed that the continuum limit still applies to the gas phase when the pressure is as low as 11 Pa (Li et al, 2019;Luo et al, 2019). The fusion enthalpy and the solidus and liquidus temperatures are assumed to undergo a negligible change when changing the ambient pressure.…”

Section: Mathematical Model Descriptionmentioning

confidence: 99%

CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing

Abadi

Hagqvist²,

Sikström³

et al. 2022

Front. Space Technol.

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Additive manufacturing of parts on-site in space requires investigating the feasibility of adapting to zero-gravity and near-vacuum conditions, a technology applied today on Earth at standard conditions. While a few studies have been conducted for powder bed fusion, a feasibility study remains to be explored for direct energy deposition using a laser beam and a metal wire. This is the purpose of this study, which is conducted using a modeling approach based on computational fluid dynamics. The simulation model developed includes melting, re-solidification, vaporization, prediction of beam energy absorption as a function of the local surface temperature and curvature, ray tracing, tracking of free surface deformation and metal transfer, and wire-resistive heating. The study is carried out by starting from process parameters suited for stable on-Earth metal deposition. These conditions were also studied experimentally to validate the simulation model, leading to satisfactorily results. A total of three other test cases with ambient pressure lowered down to near-vacuum and/or gravitation down to zero are investigated. It is found that, compared to on-Earth conditions, in-space conditions can induce vaporization of the metal alloy that is large enough to result in a curvature of the melt pool free surface but too small to lead to the formation of a keyhole. The in-space conditions can also modify the force balance at the liquid melt bridge between the wire and the melt pool, leading to small changes in the curvature and temperature field at the free surface of the wire tip. Among the observed consequences are a small increase of the melt pool length and a small elevation of the bead height. More importantly, for process control, changing to in-space conditions might also affect the stability of the process, which could be assessed through the width of the liquid metal bridge. However, by using appropriate process control to maintain a continuous liquid metal bridge, it is concluded that direct energy deposition of metal using a laser and a wire could be used for manufacturing metal parts in-space in a tempered atmosphere.

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Section: Mathematical Model Descriptionmentioning

confidence: 99%

CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing

Abadi

Hagqvist²,

Sikström³

et al. 2022

Front. Space Technol.

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“…These authors and others have studied only the formation of the molten pool. In addition, the molten pool images of these studies (especially for the melting of a powder bed) are not always of sufficient quality to determine the molten pool morphology [10,[38][39][40][41][42]. Therefore, these studies cannot be used to validate a complete simulation (thermo-fluid-mechanical simulation) of thermomechanical processes.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Thermomechanical Processes: Laser Welding and Melting of a Powder Bed

et al. 2020

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In this study, an experimental approach was developed to analyze and better understand the laser welding and melting of a powder bed process. Different optical diagnostics tools (high-speed camera, infrared camera, pyrometer, etc.) were applied to measure different physical quantities (molten pool morphology, temperature field, residual stresses, and distortions). As a result, measurements during the laser welding process facilitated the building of a database of experimental results (experimental benchmarks). The study of the melting of a powder bed enabled a better understanding of the physics related to the formation and behavior of the molten pool. These results can be used by researchers to improve and validate numerical simulations of these processes.

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“…2와 같이 16,17) . Youhei (a) S355 steel 16) , and (b) Al 5052 alloy 19) Journal of Welding and Joining, Epub ahead of print 수치해석적인 접근을 통해 키홀의 거동을 예측하기도 하였다 4,14,39) . 대기압에 비해 0.01 kPa 진공도에서는 고속카메라를 활용하여 용융풀 표면에서의 변동성이 분석된 사례가 존재하며 35,37,42) , 키홀의 거동을 관찰하 는 방식과 마찬가지로 내열 글래스를 활용하여 키홀 후 면부의 용융풀 거동이 관찰되기도 하였다 15) (Fig.…”

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Review on Vacuum Laser Beam Welding

Lee¹,

Cheon²,

Kim³

2022

Journal of Welding and Joining

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Vacuum laser beam welding (VLBW) exhibits better welding characteristics, e.g., deep penetration, less pore, and spatter generation, compared with the conventional laser welding technique under atmospheric pressure. Low ambient pressure affects the vaporization temperature of the base material and the interaction between laser and plasma plume, which affects the behaviors of laser-induced plasma plume, keyhole, and weld pool flow. This review introduces improvements in welding characteristics such as penetration depth, pore, and spatter generation in the VLBW process. The effect of ambient pressure on welding characteristics was reviewed, and the behavior of laser-induced plume, keyhole, and molten pool under reduced ambient pressure was discussed to understand the mechanisms for enhanced weldability.

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Numerical and experimental study on keyhole and melt flow dynamics during laser welding of aluminium alloys under subatmospheric pressures

Cited by 71 publications

References 36 publications

CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing

CFD-Based Feasibility Study of Laser-Directed Energy Deposition With a Metal Wire for On-Orbit Manufacturing

Experimental Study of Thermomechanical Processes: Laser Welding and Melting of a Powder Bed

Review on Vacuum Laser Beam Welding

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