The work aims to investigate the intrinsic mechanism by which coupled laser shock peening (LSP)-shot peening (SP) modulates the surface integrity and high-cycle fatigue life of TC6 compressor blades, with a core focus on optimizing anti-fatigue manufacturing processes through innovative process design and quantitative characterization of multi-parameter synergy. Six distinct surface states were systematically established to enable comprehensive comparative analysis: non-strengthened (as-received), single SP, single SP followed by vibratory finishing (SP(Pol.)), single LSP, coupled LSP+SP, and coupled LSP+SP followed by vibratory finishing (LSP+SP(Pol.)). Three blades were tested per state to ensure statistical reliability of experimental data, eliminating random errors caused by individual blade differences. A rigorous experimental characterization system was employed to capture key surface integrity parameters: a laser confocal microscope was used to quantify surface roughness parameters (Ra, Rq, Rz, Rsm), with a 4 mm test length and Gaussian filters were configured for Ra ranges of 0.1-2 μm to ensure accuracy of roughness measurement. An X-ray diffractometer was employed to map residual stress distribution on the surface and along the depth direction, with depth-dependent measurements conducted via layer-by-layer electrolytic corrosion to reveal the full stress field profile. An electron backscatter diffraction (EBSD) system was adopted to analyze grain size evolution in the surface and subsurface layers, capturing microstructural changes induced by different strengthening processes and high-cycle fatigue tests were conducted on an electric vibration system to simulate the actual service vibration conditions of blades, ensuring the fatigue life data reflects real operational performance. Key original findings center on three critical innovations that address long-standing limitations of single strengthening processes. Firstly, coupled LSP+SP achieves synergistic optimization of residual stress, a breakthrough unattainable by single LSP or SP. Its surface residual compressive stress reaches -682.6 MPa, which is slightly higher than single SP's -644.8 MPa and significantly higher than single LSP's -411.4 MPa, while the residual compressive stress layer depth is 338 μm, far deeper than single SP's 178 μm and only slightly shallower than single LSP's 389 μm. This resolves the inherent trade-off in single strengthening: single LSP fails to provide sufficient surface stress to suppress crack initiation, while single SP cannot form a deep enough stress field to inhibit crack propagation. Secondly, coupled strengthening induces superior grain refinement that enhances material mechanical properties through the Hall-Petch effect. EBSD results show that LSP+SP-treated blades have a surface grain size of 1.54 μm, a 41.2% reduction from the non-strengthened state (2.62 μm), outperforming those treated by single SP (1.77 μm, 32.4% reduction) and single LSP (2.13 μm, 18.7% reduction). The finer grain structure increases grain boundary density, which acts as a barrier to dislocation movement, thereby improving the material's resistance to microcrack formation and propagation. Thirdly, integrating vibratory finishing with coupled strengthening maximizes fatigue life improvement by eliminating surface stress concentration sources. Compared to the non-strengthened state, LSP+SP boosts fatigue life by 231.9%, vibratory finishing (removing 5-10 μm of the surface layer to eliminate SP-induced pits) further increases this to 269.9%, far exceeding single SP (165.9%, 212.3% post-polishing) and single LSP (48.3%). Mechanistically, the superiority of coupled LSP+SP stems from its sequential process logic: LSP first establishes a deep residual compressive stress field to inhibit crack propagation by reducing the stress intensity factor at the crack tip, then SP superimposes higher surface residual compressive stress to offset external cyclic tensile stress (delaying crack initiation) and refines surface grains to enhance material toughness and vibratory finishing eliminates surface pits (which act as stress concentration points), fully releasing the synergistic effects of residual stress and grain refinement. This work demonstrates that coupled LSP+SP with vibratory finishing is an effective anti-fatigue manufacturing method for TC6 compressor blades, providing direct technical guidance for optimizing surface strengthening processes of aero-engine blades, prioritizing multi-parameter synergy over single-parameter enhancement.
Key words
compressor blade /
shot peening /
laser shock peening /
coupled peening /
surface integrity /
fatigue life
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] ZHANG M, LIU Y, WANG W Q, et al.The Fatigue of Impellers and Blades[J]. Engineering Failure Analysis, 2016, 62: 208-231.
[2] SUN S, LIU S J, HE W W, et al.Predicting High-Cycle Fatigue Strength and Three-Dimensional Fatigue Crack Growth in Simulated Compressor Blade by Phase-Field Model[J]. Aerospace Science and Technology, 2025, 159: 110009.
[3] DING X, HUANG D W, YAN X J, et al.Effect of Pneumatic Shot Peening on the High and Low Cycle Combined Fatigue Life of K403 Turbine Blades[J]. Fatigue & Fracture of Engineering Materials & Structures, 2021, 44(6): 1439-1454.
[4] TANG Y, ZHANG Y K, GE M Z, et al.Influence of Double-Side Symmetric Oblique Laser Shock Peening on Shape Deviation, Surface Integrity, and Fatigue Properties of the Blades in Small-Sized Blisk[J]. International Journal of Fatigue, 2024, 186: 108427.
[5] ZHANG J Y, YAO C F, ZHUO W W, et al.Optimization of Shot Peening Parameters for Blades Based on the Constraint of Equivalent Residual Stress-Induced Deformation[J]. The International Journal of Advanced Manufacturing Technology, 2024, 131(7): 3781-3792.
[6] MAHARJAN N, RAMESH T, WANG Z C.High Energy Laser Shock Peening of Ti6Al4V Alloy without any Protective Coating[J]. Applied Surface Science, 2023, 638: 158110.
[7] LIN Q J, LIU H J, ZHU C C, et al.Investigation on the Effect of Shot Peening Coverage on the Surface Integrity[J]. Applied Surface Science, 2019, 489: 66-72.
[8] JIA M Y, WANG Y L, YUE J F, et al.Recent Progress in Laser Shock Peening: Mechanism, Laser Systems and Development Prospects[J]. Surfaces and Interfaces, 2024, 44: 103757.
[9] TAN L, YAO C F, ZHANG D H, et al.Evolution of Surface Integrity and Fatigue Properties after Milling, Polishing, and Shot Peening of TC17 Alloy Blades[J]. International Journal of Fatigue, 2020, 136: 105630.
[10] SUN Y Q, YAO C F, TAN L, et al.Surface Integrity and Fatigue Failure Behavior of Nickel Based Alloy Blades: After Cutting, Vibration Finishing and Shot Peening[J]. Engineering Failure Analysis, 2025, 167: 109034.
[11] WU J F, CHE Z G, ZOU S K, et al.Surface Integrity of TA19 Notched Simulated Blades with Laser Shock Peening and Its Effect on Fatigue Strength[J]. Journal of Materials Engineering and Performance, 2020, 29(8): 5184-5194.
[12] BAE S, KIM Y, JUNG J, et al.Effects of Laser Shock Peening on Inconel 738LC to Improve Mechanical and Fatigue Characteristics[J]. Optics & Laser Technology, 2024, 171: 110290.
[13] ZHANG Y X, GUO W, SHI J X, et al.Improved Rotating Bending Fatigue Performance of Laser Directed Energy Deposited Ti6Al4V Alloys by Laser Shock Peening[J]. Journal of Alloys and Compounds, 2024, 980: 173664.
[14] HE B Y, SOADY K A, MELLOR B G, et al.Effects of Shot Peening on Short Crack Growth Rate and Resulting Low Cycle Fatigue Behaviour in Low Pressure Turbine Blade Material[J]. Materials Science and Technology, 2013, 29(7): 788-796.
[15] WU J Z, WEI P T, LIU H J, et al.Effect of Shot Peening Intensity on Surface Integrity of 18CrNiMo7-6 Steel[J]. Surface and Coatings Technology, 2021, 421: 127194.
[16] ZHOU L C, PAN X L, SHI X S, et al.Research on Surface Integrity of Ti-6Al-4V Alloy with Compound Treatment of Laser Shock Peening and Shot Peening[J]. Vacuum, 2022, 196: 110717.
[17] SOYAMA H, KORSUNSKY A M.A Critical Comparative Review of Cavitation Peening and Other Surface Peening Methods[J]. Journal of Materials Processing Technology, 2022, 305: 117586.
[18] OUYANG P X, DONG Z C, LUO X K, et al.Effect of Combined Treatment of Laser Shock Peening and Shot Peening on Fatigue Performance of Laser-Powder-Bed- Fusioned GH4169 Nickel-Based Alloy[J]. Optics & Laser Technology, 2025, 182: 112141.
[19] ZHU W G, MA C, ZHANG C H, et al.Fatigue Crack Propagation Behavior in Ti-6Al-4V Alloy with Surface Gradient Structure Fabricated by High-Energy Shot Peening[J]. Transactions of Nonferrous Metals Society of China, 2023, 33(10): 3003-3016.
[20] MALEKI E, UNAL O, AMANOV A.Novel Experimental Methods for the Determination of the Boundaries between Conventional, Severe and over Shot Peening Processes[J]. Surfaces and Interfaces, 2018, 13: 233-254.
[21] WANG Q W, MA Y, FU X S, et al.Numerical Simulation Study of Combined Shot Peening and Laser Shock Peening on Surface Integrity of Ti-6Al-4V Titanium Alloy[J]. Surface and Coatings Technology, 2024, 487: 130997.
[22] LUO X K, DANG N, WANG X.The Effect of Laser Shock Peening, Shot Peening and Their Combination on the Microstructure and Fatigue Properties of Ti-6Al-4V Titanium Alloy[J]. International Journal of Fatigue, 2021, 153: 106465.
[23] LAINÉ S J, KNOWLES K M, DOORBAR P J, et al.Microstructural Characterisation of Metallic Shot Peened and Laser Shock Peened Ti-6Al-4V[J]. Acta Materialia, 2017, 123: 350-361.
[24] ZHANG Y T, ZHANG K, HU Z, et al.The Synergetic Effects of Shot Peening and Laser-Shot Peening on the Microstructural Evolution and Fatigue Performance of a Medium Carbon Steel[J]. International Journal of Fatigue, 2023, 166: 107246.
[25] PUSHP P, DASHARATH S M, ARATI C.Classification and Applications of Titanium and Its Alloys[J]. Materials Today: Proceedings, 2022, 54: 537-542.
[26] GB/T 10610—2009 产品几何技术规范(GPS) 表面结构轮廓法评定表面结构的规则和方法[S].
GB/T 10610—2009 Geometrical Product Specifications (GPS) - Surface texture:Profile Method - Rules and Procedures for the Assessment of Surface Texture[S].
[27] HB5277—2021, 发动机叶片及材料振动疲劳试验方法[S].
HB5277—2021, Vibration Fatigue Testing Method for Aero Engine Blades and Materials[S].
[28] ZHANG Z, ZHANG Y K, LOUGHLIN M, et al.Experimental Research on Global Deformation and Through- Thickness Residual Stress in Laser Peen Formed Aluminum Plates[J]. Surfaces and Interfaces, 2021, 25: 101241.
[29] LUO K Y, LIU B, WU L J, et al.Tensile Properties, Residual Stress Distribution and Grain Arrangement as a Function of Sheet Thickness of Mg-Al-Mn Alloy Subjected to Two-Sided and Simultaneous LSP Impacts[J]. Applied Surface Science, 2016, 369: 366-376.
[30] FUJITA K, NAKAZAWA K, FUJIWARA H, et al.Effect of Grain Size on Fatigue Limit in CrMnFeCoNi High- Entropy Alloy Fabricated by Spark Plasma Sintering under Four-Point Bending[J]. Materials Science and Engineering: A, 2022, 857: 144121.
[31] 卢柯, 刘学东, 胡壮麒. 纳米晶体材料的Hall-Petch关系[J]. 材料研究学报, 1994, 8(5): 385-391.
LU K, LIU X D, HU Z Q.The hall-Petch Relation in Nanocrystalline Materials[J]. Chinese Journal of Materials Research, 1994, 8(5): 385-391.
Funding
National Key Research and Development Program of China (2024YFB4609000); National Science and Technology Major Project (J2019-Ⅳ-0009-0077, Y2022-Ⅶ-0007-0049); Beijing Natural Science Foundation (3252007)
PDF(18907 KB)
