• Chinese Journal of Lasers
  • Vol. 49, Issue 8, 0802008 (2022)
Yifei Wang1, Zhou Yu2, Kangmei Li1、3、4, and Jun Hu2、*
Author Affiliations
  • 1College of Mechanical Engineering, Donghua University, Shanghai 201620, China
  • 2Institute of Artificial Intelligence, Donghua University, Shanghai 201620, China
  • 3Shanghai Collaborative Innovation Center for High Performance Fiber composites, Donghua University, Shanghai 201620, China
  • 4State Key Laboratory of Digital Manufacturing Equipment & Technology, Wuhan 430074, Hubei, China
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    DOI: 10.3788/CJL202249.0802008 Cite this Article Set citation alerts
    Yifei Wang, Zhou Yu, Kangmei Li, Jun Hu. Numerical Simulation of Micro-pit Morphology of Titanium Alloy Ablated by Nanosecond Laser[J]. Chinese Journal of Lasers, 2022, 49(8): 0802008 Copy Citation Text show less
    Mesh convergence analysis
    Fig. 1. Mesh convergence analysis
    Setting of grid and boundary conditions
    Fig. 2. Setting of grid and boundary conditions
    Change of ablation temperature within a single pulse period. (a) Ablation time is 150 ns; (b) ablation time is 450 ns; (c) ablation time is 2 μs; (d) ablation time is 4 μs
    Fig. 3. Change of ablation temperature within a single pulse period. (a) Ablation time is 150 ns; (b) ablation time is 450 ns; (c) ablation time is 2 μs; (d) ablation time is 4 μs
    Influence of heat dissipation conditions on temperature field. (a) Temperature change during two ablation cycles; (b) effect of thermal conductivity; (c) effect of air convection; (d) effect of surface radiation
    Fig. 4. Influence of heat dissipation conditions on temperature field. (a) Temperature change during two ablation cycles; (b) effect of thermal conductivity; (c) effect of air convection; (d) effect of surface radiation
    Temperature field in the second pulse period. (a) Ablation time is 20 μs; (b) ablation time is 20.10 μs; (c) ablation time is 20.15 μs; (d) ablation time is 20.20 μs
    Fig. 5. Temperature field in the second pulse period. (a) Ablation time is 20 μs; (b) ablation time is 20.10 μs; (c) ablation time is 20.15 μs; (d) ablation time is 20.20 μs
    Velocity field within a single pulse period when Marangoni is not considered. (a) Ablation time is 100 ns; (b) ablation time is 150 ns; (c) ablation time is 200 ns; (d) ablation time is 1000 ns
    Fig. 6. Velocity field within a single pulse period when Marangoni is not considered. (a) Ablation time is 100 ns; (b) ablation time is 150 ns; (c) ablation time is 200 ns; (d) ablation time is 1000 ns
    Velocity field in a single pulse period when Marangoni is considered. (a) Ablation time is 100 ns; (b) ablation time is 150 ns; (c) ablation time is 200 ns; (d) ablation time is 1000 ns
    Fig. 7. Velocity field in a single pulse period when Marangoni is considered. (a) Ablation time is 100 ns; (b) ablation time is 150 ns; (c) ablation time is 200 ns; (d) ablation time is 1000 ns
    Melting and vaporization processes of titanium alloy. (a) Ablation time is 90 ns; (b) ablation time is 120 ns; (c) ablation time is 200 ns; (d) ablation time is 1.5 μs
    Fig. 8. Melting and vaporization processes of titanium alloy. (a) Ablation time is 90 ns; (b) ablation time is 120 ns; (c) ablation time is 200 ns; (d) ablation time is 1.5 μs
    Liquid phase migration and sputtering. (a) Ablation time is 3 μs; (b) ablation time is 3.5 μs; (c) ablation time is 3.6 μs; (d) ablation time is 3.65 μs
    Fig. 9. Liquid phase migration and sputtering. (a) Ablation time is 3 μs; (b) ablation time is 3.5 μs; (c) ablation time is 3.6 μs; (d) ablation time is 3.65 μs
    Solidification process of liquid titanium alloy. (a) Ablation time is 5 μs; (b) ablation time is 10 μs; (c) ablation time is 15 μs; (d) ablation time is 20 μs
    Fig. 10. Solidification process of liquid titanium alloy. (a) Ablation time is 5 μs; (b) ablation time is 10 μs; (c) ablation time is 15 μs; (d) ablation time is 20 μs
    Surface morphology of titanium alloy micro-pits. (a) Pa=7.5 W, f=20 kHz, N=1; (b) Pa=20 W, f=50 kHz, N=1
    Fig. 11. Surface morphology of titanium alloy micro-pits. (a) Pa=7.5 W, f=20 kHz, N=1; (b) Pa=20 W, f=50 kHz, N=1
    Simulation and experimental morphologies when number of ablations is 1 and 3. (a) Simulated morphology when number of ablation is 1; (b) simulated morphology when number of ablation is 3; (c) optical morphology when number of ablation is 1; (d) optical morphology number of ablation is 3
    Fig. 12. Simulation and experimental morphologies when number of ablations is 1 and 3. (a) Simulated morphology when number of ablation is 1; (b) simulated morphology when number of ablation is 3; (c) optical morphology when number of ablation is 1; (d) optical morphology number of ablation is 3
    Comparison of experimental sizes and simulation results. (a) H1 and H2;(b) D1and D2
    Fig. 13. Comparison of experimental sizes and simulation results. (a) H1 and H2;(b) D1and D2
    Influence of laser process parameters on ablation size. (a) Effect of laser flux on ablation area;(b)(d) changes of migration speed and size of liquid phase in different ablation stages when number of ablation times is 10
    Fig. 14. Influence of laser process parameters on ablation size. (a) Effect of laser flux on ablation area;(b)(d) changes of migration speed and size of liquid phase in different ablation stages when number of ablation times is 10
    Parameter from ablation center to ablation edge at different ablation times in the tenth pulse period. (a) Temperature; (b) recoil pressure; (c) X component of surface tension ; (d) Y component of surface tension
    Fig. 15. Parameter from ablation center to ablation edge at different ablation times in the tenth pulse period. (a) Temperature; (b) recoil pressure; (c) X component of surface tension ; (d) Y component of surface tension
    f /kHz20253035404550
    Pa /W7.59.611.713.916.018.220.0
    Table 1. Variation of average power with repetition frequency
    ElementTiAlVFe
    Mass fraction /%91.45.62.70.1
    Table 2. Chemical composition of Ti6Al4V
    Material parametersSymbolValueUnit
    Melting pointTm1923K
    Vaporization temperatureTvap3533K
    Latent heat of fusionLf2.86×105J/kg
    Latent heat of vaporizationLv9.83×106J /kg
    Specific heat capacityCp483+0.22TT≤1268 K;J /(kg·K)
    412+0.18T,1268 K<T<1923 K
    831,T≥1923 K
    Thermal conductivityk1.26+0.016T, T≤1268 K;W /(m·K)
    3.51+0.013T, 1268 K<T<1923 K
    -12.75+0.024T, T≥1923 K
    Solid phase densityρs4420-0.154×(T-298)kg/m3
    Liquid densityρl3920-0.680×(T-1923)kg /m3
    Dynamic viscosityμexp(-1.6+5346/T) ×10-3N /(m·s)
    Surface tensionσ1.53-0.28×10-3(T-1941)N /m
    Surface tension coefficientγ-2.8×10-4N /(m·K)
    Standard atmospheric pressurePb1.01×105Pa
    Table 3. Thermodynamic parameters of titanium alloy
    Yifei Wang, Zhou Yu, Kangmei Li, Jun Hu. Numerical Simulation of Micro-pit Morphology of Titanium Alloy Ablated by Nanosecond Laser[J]. Chinese Journal of Lasers, 2022, 49(8): 0802008
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