Simulation of the main physical processes in remote laser penetration with large laser spot size

Khairallah, Saad A.; Anderson, Andrew T.; Rubenchik, Alexander M.; Florando, J.N.; Wu, Shuai; Lowdermilk, H

doi:10.1063/1.4918284

Cited by 27 publications

(6 citation statements)

References 11 publications

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“…Recoil phenomena occur on the material surface when evaporation takes place. The recoil pressure P recoil can be deduced using Anisimov's method [33], expressed as follows [34][35][36]:…”

Section: Surface Tension and Marangoni Effectmentioning

confidence: 99%

Evolution of molten pool during selective laser melting of Ti–6Al–4V

Zhang

Liu

et al. 2018

J. Phys. D: Appl. Phys.

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The characteristics of molten pools provide valuable insight into the complexity of the metal additive manufacturing process, which has a significant influence on the quality of the parts built using this process. In our work, we develop a three-dimensional multiphysics finite element model of a selective laser melting (SLM) process on a Ti-6Al-4V alloy. The dynamic characteristics of the molten pool are studied by multiphysics simulation with consideration of phase transitions, recoil pressure, surface tension, and Marangoni effect. The results show the time-evolution of temperature distribution, flow field, and surface morphology of a single track during the SLM process. The recoil pressure caused by evaporation plays a significant role in molten pool dynamics and induces a depression at the head of the molten pool. As a result of the backward Marangoni flow, the material is shifted to the tail region and a vortex is generated. In addition, a protrusion is presented at the middle and start points of the scanned track, while a depression is formed at both sides and at the terminal point. The simulation and the experimental results on the surface morphology of the molten track during the SLM process are in good agreement. Furthermore, it is found that metal evaporation may take place not only on the surface of the molten pool but also inside it, due to the drop in pressure. This is a significant contributor to the formation of porosity in SLM parts.

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“…Recoil phenomena occur on the material surface when evaporation takes place. The recoil pressure P recoil can be deduced using Anisimov's method [33], expressed as follows [34][35][36]:…”

Section: Surface Tension and Marangoni Effectmentioning

confidence: 99%

Evolution of molten pool during selective laser melting of Ti–6Al–4V

Zhang

Liu

et al. 2018

J. Phys. D: Appl. Phys.

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“…In [83], the model proposed in [81] has been extended to also (implicitly) account for the effects of recoil pressure in the evaporation zone below the laser beam on the subjacent melt pool flow, Marangoni convection, as well as evaporative and radiative surface cooling (see also [82] for more details of the model). Moreover, a more detailed resolution of the laser energy absorption has been achieved based on a ray-tracing model as discussed in Section 2.1.2.…”

Section: Mesoscopic Simulation Modelsmentioning

confidence: 99%

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation, and Experimentation

Meier

Penny

Zou

et al. 2017

Annual Rev Heat Transfer

121

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Among the many additive manufacturing (AM) processes for metallic materials, selective laser melting (SLM) is arguably the most versatile in terms of its potential to realize complex geometries along with tailored microstructure. However, the complexity of the SLM process, and the need for predictive relation of powder and process parameters to the part properties, demands further development of computational and experimental methods. This review addresses the fundamental physical phenomena of SLM, with a special emphasis on the associated thermal behavior. Simulation and experimental methods are discussed according to three primary categories. First, macroscopic approaches aim to answer questions at the component level and consider for example the determination of residual stresses or dimensional distortion effects prevalent in SLM. Second, mesoscopic approaches focus on the detection of defects such as excessive surface roughness, residual porosity or inclusions that occur at the mesoscopic length scale of individual powder particles. Third, microscopic approaches investigate the metallurgical microstructure evolution resulting from the high temperature gradients and extreme heating and cooling rates induced by the SLM process. Consideration of physical phenomena on all of these three length scales is mandatory to establish the understanding needed to realize high part quality in many applications, and to fully exploit the potential of SLM and related metal AM processes. arXiv:1709.09510v1 [physics.app-ph] 4 Sep 2017 1.4. Differentiation of related additive manufacturing processes for metals References and comparisons to other powder-bed metal AM processes such as electron beam melting (EBM) and selective laser sintering (SLS) will be useful from time to time in the foregoing discussion [97,98,50,52,68]. Similar to SLM, the EBM process represents a powder bed-based additive manufacturing process where pre-defined contours are selectively melted in successively deposited powder layers. While SLM applies a laser beam as energy source, EBM is based on an electron beam. EBM is only applicable to electrically conductive materials and has to be

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“…Because large spot sizes require much higher laser powers, while maintaining similar intensities to those typically used for small spot sizes, large spot size applications could not be developed until the advent of such powerful lasers. As a result, there are only a few reports on applications using large spot sizes in the centimetre range [8][9][10][11][12][13][14][15][16][17][18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

Reich,

Goesmann,

Heunoske

et al. 2023

Preprint

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In laser materials processing, energy losses due to reflection, heat conduction and thermal radiation play an important role. In this publication, we show that with increasing laser intensity, the energy lost within the sample becomes less important for metal perforation processes. We compare the laser-matter interaction of aluminium and steel plates. Material parameters such as density, melting point and especially thermal conductivity differ strongly, leading to much longer perforation times for aluminium in comparison to steel at laser powers of 20 kW. However, this behaviour changes at laser powers of more than 80 kW where the perforation times of aluminium become shorter than the corresponding times for steel. By comparing experimental data and simulations, we conclude that thermal conduction is the dominant factor of energy loss at low powers, but is reduced at high laser powers.

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Simulation of the main physical processes in remote laser penetration with large laser spot size

Cited by 27 publications

References 11 publications

Evolution of molten pool during selective laser melting of Ti–6Al–4V

Evolution of molten pool during selective laser melting of Ti–6Al–4V

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation, and Experimentation

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

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