Analysis on the influence of vapor capillary aspect ratio on pore formation in laser beam welding of aluminum

Hummel, Marc; Hagenlocher, Christian; Haeusler, A.; Hollatz, Sören; Lind, Jannik; Olowinsky, Alexander; Gillner, Arnold; Beckmann, Felix; Weber, Rudolf; Graf, Thomas; Häfner, Constantin

doi:10.1016/j.jmatprotec.2023.117862

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Increasing the laser beam velocity had the effect of enlarging the keyhole and enhancing keyhole stability. 24,25 Based on a previous investigation, 26 when the welding velocity vw as combined with the beam oscillation velocity, the laser beam velocity vL was usually defined by Equation (7). Where vx and vy were the velocity components in the welding direction and vertical welding direction, respectively; fx and fy were the frequency; Ax and Ay were the amplitude; φx and φy were the respective phase angles in x - and y -direction, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Effect of beam oscillation frequency on porosity in laser welding of aluminum alloy lap-butt joints

Tan,

Zhang,

Liu

et al. 2024

Science and Technology of Welding and Joining

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Many investigations into laser oscillations for mitigating severe porosity in aluminum alloys have involved trading off penetration depth, potentially disrupting the porosity suppression mechanism. In this study, an oscillation laser butt-lap welding technique was designed, and the effect of oscillation frequency on cross-section morphologies and porosity rate was investigated while maintaining the constant weld depth. The findings unveiled that heightened oscillation frequencies led to diminished porosity levels, and this pattern remained consistent, even in cases where weld depths were extended. High-frequency laser beam oscillation enhanced the stability of the keyhole, increased the duration of the molten pool existence, and reduced porosity to 0.17%. Thus, this study offered significant insights into the impact of oscillation on laser welding of aluminum alloys.

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Section: Resultsmentioning

confidence: 99%

Section: Influencing Mechanism Of the Oscillation Laser On Porositymentioning

confidence: 99%

Effect of beam oscillation frequency on porosity in laser welding of aluminum alloy lap-butt joints

Tan,

Zhang,

Liu

et al. 2024

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

show abstract

“…Identical to this study, the porosity of the weld seams is calculated by the quotient of weld seam area to pore area. 11…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

In situ synchrotron observation of the vapor capillary geometry in laser welding of copper with 1030 nm and 515 nm laser beam sources

Hummel

Meier

Olowinsky

et al. 2023

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XII

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Laser welding as a tool for manufacturing highly precise parts for electronic and electro mobility components is gaining worldwide importance. The precise control of energy input is one paramount challenge of welding highly reflective materials with high thermal conductivity such as copper and its alloys. Laser beam wavelengths in the visible range show an increase in absorptivity from < 5% (1030 nm) to ≥ 40% (515 nm) on copper at room temperature and open new options in material processing technologies. This paper presents the in situ observation of laser welding processes on Cu-ETP and CuSn6 with laser beam sources of 1030 nm and 515 nm wavelength using synchrotron radiation at DESY Petra 3 Beamline P07 EH4. The influence of laser power from 1 kW up to 4 kW and feed rates from 50 mm/s up to 500 mm/s on vapor capillary geometry and dynamics with same focal diameters is compared. For the investigations, a synchrotron beam of 2x2 mm2 in size with a photon energy of 89 keV is used for investigation. The material samples are analyzed by means of material phase contrast method to show boundaries between solid, liquid, and gaseous material phases. It is found, that both welding processes show a different geometry of the vapor capillary. A different sensitivity to changes of the feed rate of the welding process is observed. The vapor capillary of the 1030 nm welding process tends to be more sensitive on feed rate changes while showing an overall better weld seam quality. When welding with 515 nm, comparatively higher feed rates lead to better welding results.

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Unveiling thermo‐fluid dynamic phenomena in laser beam welding

Forster,

Rothfelder,

Krakhmalev

et al. 2024

Proc Appl Math and Mech

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Laser beam welding (LBW), as a non‐contact process with short cycle times and small heat affected zone, is a key technology for automated metal fabrication. Despite its efficiency, the susceptibility of certain alloys to solidification cracks remains a significant challenge. These cracks emerge in the transition zone between liquid and solid phases during the solidification process. Thermo‐fluid dynamic processes within the melt pool play a crucial role in solidification crack formation during LBW, influencing heat distribution, mass transport, and consequently, the microstructure and mechanical properties of the weld. An in‐depth exploration of thermo‐fluid dynamics within the melt pool, contributes to an improved understanding of the correlations between process parameters and melt pool flow aiming to avoid solidification cracks. Therefore, in situ process investigations were conducted at beamline P07 of PETRA III at the German Electron and Synchrotron (DESY). 1.4404 stainless steel specimen containing an 5 wt.% of tungsten particles, serving as tracer, were additively manufactured using laser powder bed fusion. The tungsten particles are evenly distributed within the samples. High‐speed synchrotron x‐ray imaging of the process zone allowed for detailed in situ analyses. Leveraging the lower x‐ray absorption coefficients of the base steel material compared to tungsten, the particles appeared as dark dots in the images. The experimental setup involved blind welds on the samples, where a portion of the sample was melted by the laser beam, forming a molten pool in the center while the edges remained intact. The uniform distribution of the particles in the sample means that the movement of the particles in the molten pool is overlaid by static particles located in the unmelted edges of the sample. To enhance the observation and tracking of particle movement within the melt pool, the image contrast was optimized, and static particles were filtered out. The resulting images offer a visual representation of thermo‐fluid dynamical flows during LBW, based on the movement of tracer particles. Analysis was performed using an on Hessian blob detection and Kalman filter based tracking tool [1]. The results of this investigation provide valuable insights into the intricacies of thermo‐fluid dynamics during LBW, offering a foundation for the advancement of numerical modeling and simulation tools in the field of LBW.

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Analysis on the influence of vapor capillary aspect ratio on pore formation in laser beam welding of aluminum

Cited by 6 publications

References 13 publications

Effect of beam oscillation frequency on porosity in laser welding of aluminum alloy lap-butt joints

Effect of beam oscillation frequency on porosity in laser welding of aluminum alloy lap-butt joints

In situ synchrotron observation of the vapor capillary geometry in laser welding of copper with 1030 nm and 515 nm laser beam sources

Unveiling thermo‐fluid dynamic phenomena in laser beam welding

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