• Chinese Journal of Lasers
  • Vol. 52, Issue 12, 1202201 (2025)
Daihua Li1, Weifeng He1,2,*, Xiangfan Nie1,2, Yuhang Wu1, and Jile Pan2
Author Affiliations
  • 1National Key Lab of Aerospace Power System and Plasma Technology, School of Aviation Engineering, Air Force Engineering University, Xi’an 710038, Shaanxi , China
  • 2National Key Lab of Aerospace Power System and Plasma Technology, Xi’an Jiaotong University, Xi’an 710038, Shaanxi , China
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    DOI: 10.3788/CJL250513 Cite this Article Set citation alerts
    Daihua Li, Weifeng He, Xiangfan Nie, Yuhang Wu, Jile Pan. Enhancing Ultra-High Cycle Fatigue Properties of GH4169 Alloy Using Microscale Laser Shock Peening[J]. Chinese Journal of Lasers, 2025, 52(12): 1202201 Copy Citation Text show less
    Metallographic structure of GH4169 with EDS analysis results of phase indicated by arrow shown in inset
    Fig. 1. Metallographic structure of GH4169 with EDS analysis results of phase indicated by arrow shown in inset
    Schematic diagram of ultra-high cycle fatigue specimen (unit: mm)
    Fig. 2. Schematic diagram of ultra-high cycle fatigue specimen (unit: mm)
    Microscale laser shock peening treatment. (a) Microscale laser shock peening diagram; (b) microscale laser shock peening area and scanning path of microscale laser shock peening
    Fig. 3. Microscale laser shock peening treatment. (a) Microscale laser shock peening diagram; (b) microscale laser shock peening area and scanning path of microscale laser shock peening
    S-N curves of different samples
    Fig. 4. S-N curves of different samples
    Ultra-high cycle fatigue fracture of untreated specimen (σa=425 MPa, Nf=1.56×107). (a) General view of fatigue fracture; (b) crack growth region and crack initiation region; (c) enlarged view of crack initiation region
    Fig. 5. Ultra-high cycle fatigue fracture of untreated specimen (σa=425 MPa, Nf=1.56×107). (a) General view of fatigue fracture; (b) crack growth region and crack initiation region; (c) enlarged view of crack initiation region
    Ultra-high cycle fatigue fracture of 62 mJ&1 time specimen (σa=425 MPa, Nf=1.21×108). (a) General view of fatigue fracture; (b) general view of crack initiation region; (c) edge of crack initiation region; (d) enlarged view of crack initiation region
    Fig. 6. Ultra-high cycle fatigue fracture of 62 mJ&1 time specimen (σa=425 MPa, Nf=1.21×108). (a) General view of fatigue fracture; (b) general view of crack initiation region; (c) edge of crack initiation region; (d) enlarged view of crack initiation region
    Ultra-high cycle fatigue fracture of 62 mJ&3 times specimen (σa=425 MPa, Nf=7.88×108). (a) General view of fatigue fracture;(b) general view of crack initiation region; (c) facet morphology;(d) edge of crack initiation region with carbon element distribution in inclusion shown in inset
    Fig. 7. Ultra-high cycle fatigue fracture of 62 mJ&3 times specimen (σa=425 MPa, Nf=7.88×108). (a) General view of fatigue fracture;(b) general view of crack initiation region; (c) facet morphology;(d) edge of crack initiation region with carbon element distribution in inclusion shown in inset
    Ultra-high cycle fatigue fracture of 82 mJ&1 time specimen (σa=425 MPa, Nf=4.32×108). (a) General view of fatigue fracture; (b) crack initiation region; (c) facet morphology
    Fig. 8. Ultra-high cycle fatigue fracture of 82 mJ&1 time specimen (σa=425 MPa, Nf=4.32×108). (a) General view of fatigue fracture; (b) crack initiation region; (c) facet morphology
    Three-dimensional morphologies of specimens. (a) Untreated; (b) 62 mJ&1 time; (c) 62 mJ&3 times; (d) 82 mJ&1 time
    Fig. 9. Three-dimensional morphologies of specimens. (a) Untreated; (b) 62 mJ&1 time; (c) 62 mJ&3 times; (d) 82 mJ&1 time
    Surface roughness values of specimens
    Fig. 10. Surface roughness values of specimens
    Residual stress distributions of treated specimens in gradient direction
    Fig. 11. Residual stress distributions of treated specimens in gradient direction
    Inverse pole figures and KAM diagrams of surfaces along gradient direction. (a)(b) Untreated; (c)(d) 62 mJ&1 time; (e)(f) 62 mJ&3 times; (g)(h) 82 mJ&1 time
    Fig. 12. Inverse pole figures and KAM diagrams of surfaces along gradient direction. (a)(b) Untreated; (c)(d) 62 mJ&1 time; (e)(f) 62 mJ&3 times; (g)(h) 82 mJ&1 time
    Grain size distributions of surface layer after microscale laser shock peening
    Fig. 13. Grain size distributions of surface layer after microscale laser shock peening
    FeNiMoNbTiAlSiPMnSCrC
    Bal.53.84002.99005.44000.99000.55000.05800.01100.06200.000518.24000.0250
    Table 1. Chemical compositions of GH4169 (mass fraction, %)
    ParameterTensile strength /MPaYield strength /MPaElongation /%Shrinkage /%Elastic modulus /GPa
    Value146912111731191
    Table 2. Mechanical properties of GH4169
    ParameterContent
    Constrained layerWater
    Spot diameter /mm0.36
    Power density /(GW/cm26
    Impact energy /mJ62, 82
    Overlap rate /%50%
    Impact number1,3
    Table 3. Process parameters of microscale laser shock peening
    GND densityFrequency /%
    Untreated specimen62 mJ&1 time specimen62 mJ&3 times specimen82 mJ&1 time specimen
    Average GND density0.75×1014/m20.78×1014/m20.90×1014/m20.85×1014/m2
    0×1014/m2ρGND≤2×1014/m295.9111598.0217398.0405898.03120
    2×1014/m2<ρGND≤4×1014/m23.332211.672761.736691.70007
    4×1014/m2<ρGND≤6×1014/m20.558480.255720.168890.22700
    6×1014/m2<ρGND≤8×1014/m20.143480.040800.035250.03179
    8×1014/m2<ρGND≤10×1014/m20.039570.005140.015060.00674
    10×1014/m2<ρGND≤12×1014/m20.011260.002250.002560.00225
    12×1014/m2<ρGND≤14×1014/m20.003860.001610.000960.00096
    Table 4. GND density distributions of surface layers after microscale laser shock peening under different parameters and average GND densities
    Daihua Li, Weifeng He, Xiangfan Nie, Yuhang Wu, Jile Pan. Enhancing Ultra-High Cycle Fatigue Properties of GH4169 Alloy Using Microscale Laser Shock Peening[J]. Chinese Journal of Lasers, 2025, 52(12): 1202201
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