A study on transient molten pool dynamics in laser polishing of Ti6Al4V using numerical simulation

Li, Kai; Zhao, Zhenyu; Zhou, Houming; Yin, Jie; Jin, Jingcheng

doi:10.1016/j.jmapro.2021.03.045

Cited by 29 publications

(17 citation statements)

References 34 publications

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“…In this paper, the model is based on the energy equation (Equation ( 1)), momentum equation (Equation ( 2)) and continuity equation (Equation ( 3)) as the theoretical guidance [22][23][24][25][26].…”

Section: Governing Equationsmentioning

confidence: 99%

“…where C p is the specific heat, L m is the latent heat of melting, the definition of liquid fraction f L as follow [22][23][24][25][26]…”

Section: Governing Equationsmentioning

confidence: 99%

“…(1) Heat transfer boundary condition Equation ( 7) describes the laser beam radiation which induces the thermal convection and surface to surface ambient radiation heat loss whiles the thermal insulation in boundary 4 is expressed in Equation ( 8) [22][23][24][25][26].…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…(2) Momentum boundary condition Equation ( 9) describes the velocity field at the boundary which is set as no slip wall in boundary 4 whiles the flow velocity in the r direction which is limited to zero in boundaries 2 and 3 is expressed in Equation ( 10) [25].…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…(3) Free surface boundary condition Equation (11) describes the total stress act on the free surface (boundary 1) of the molten pool. Additionally, the normal and tangential components are expressed in Equations ( 12) and (13) [22][23][24][25][26].…”

Section: Boundary Conditionsmentioning

confidence: 99%

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Numerical Simulation of Effect of Different Initial Morphologies on Melt Hydrodynamics in Laser Polishing of Ti6Al4V

Zhao

Zhou

et al. 2021

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As a surface finishing technique for rapid remelting and re-solidification, laser polishing can effectively eliminate the asperities so as to approach the feature size. Nevertheless, the polished surface quality is significantly sensitive to the processing parameters, especially with respect to melt hydrodynamics. In this paper, a transient two-dimensional model was developed to demonstrate the molten flow behavior for different surface morphologies of the Ti6Al4V alloy. It is illustrated that the complex evolution of the melt hydrodynamics involving heat conduction, thermal convection, thermal radiation, melting and solidification during laser polishing. Results show that the uniformity of the distribution of surface peaks and valleys can improve the molten flow stability and obtain better smoothing effect. The high cooling rate of the molten pool resulting in a shortening of the molten lifetime, which prevents the peaks from being removed by capillary and thermocapillary forces. It is revealed that the mechanism of secondary roughness formation on polished surface. Moreover, the double spiral nest Marangoni convection extrudes the molten to the outsides. It results in the formation of expansion and depression, corresponding to nearby the starting position and at the edges of the polished surface. It is further found that the difference between the simulation and experimental depression depths is only about 2 μm. Correspondingly, the errors are approximately 8.3%, 14.3% and 13.3%, corresponding to Models 1, 2 and 3, respectively. The aforementioned results illustrated that the predicted surface profiles agree reasonably well with the experimentally measured surface height data.

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