文献类型：期刊文献

中文题名：水导激光强化对2519A铝合金表面完整性与疲劳行为影响机理(特邀)

英文题名：Influence Mechanism of Water?Guided Laser Strengthening on Surface Integrity and Fatigue Behavior of 2519A Aluminum Alloy(Invited)

作者：张平[1];高业然[1];王雪兆[1];张腾飞[1];葛帅[1];江晓敏[1]

机构：[1]广东海洋大学机械工程学院,广东湛江524088

年份：2025

卷号：52

期号：14

起止页码：309

中文期刊名：中国激光

外文期刊名：Chinese Journal of Lasers

收录：北大核心2023、、ESCI(收录号：WOS:001533597100002)、EI(收录号：20253118877057)、WOS、北大核心

基金：广东省自然科学基金优青项目(2023A1515030171);广东省高等学校重点领域专项重点项目(2024ZDZX3053)。

语种：中文

中文关键词：水导激光强化;表面完整性;疲劳性能;2519A铝合金;裂纹萌生

外文关键词：water-guided laser strengthening;surface integrity;fatigue performance;2519A aluminum alloy;crack initiation

中文摘要：旨在探究水导激光(WGL)技术对2519A铝合金表面完整性及疲劳性能的影响机理。水导激光(WGL)技术通过将激光束耦合于高速水射流中形成稳定液柱,实现对激光能量的空间约束与焦点控制,有效避免传统激光强化中高温导致的热损伤问题。为了探究WGL技术对2519A铝合金表面完整性及疲劳性能的影响机理,系统开展了不同激光功率与冲击次数下的WGL处理试验,并与单一磨料水射流(AWJ)强化工艺进行对比,重点分析表面形貌、显微硬度、残余压应力及疲劳寿命等指标的演化规律与作用机制。结果表明,WGL处理显著优化了表面状态:最大粗糙度降幅达47.5%,表面残余压应力达287 MPa,硬化层深度增至356μm,显微硬度显著提升。在288 MPa最大应力条件下,WGL-3试样疲劳寿命较AWJ试样提高了236%。WGL技术作为激光冲击与水射流协同的复合强化工艺,实现了无热损伤的表层组织调控与多尺度强化,为高强铝合金的疲劳寿命提升提供了新途径。

外文摘要：Objective Fatigue failure represents a critical degradation mechanism in high-strength aluminum alloy components under cyclic loading,particularly in aerospace and marine structures.These failures commonly originate at surface or near-surface defects due to stress concentration and material deterioration.Enhancement of surface integrity—through increased hardness,reduced roughness,and induced compressive residual stress—is crucial for prolonging component service life.Conventional surface strengthening methods,including laser shock peening(LSP)and abrasive water jet(AWJ)peening,have shown improvements in fatigue life;however,they exhibit limitations such as thermal damage or insufficient strengthening depth.To address these constraints,this study introduces a novel hybrid approach—water-guided laser(WGL)strengthening—which combines high-energy laser pulses with confined water jet flow.The research aims to examine the effects and underlying mechanisms of WGL on surface morphology,microstructure,residual stress distribution,and fatigue life of 2519A aluminum alloy under various laser powers and impact counts.Methods WGL experiments utilize a self-developed apparatus that integrates a nanosecond-pulsed laser(1064 nm)with a high-speed water jet to generate a confined energy column.Three WGL conditions—WGL-1(low power,single impact),WGL-2(moderate power,double impact),and WGL-3(high power,double impact)—are evaluated.An AWJ-treated sample provides the control group.All specimens undergo extensive testing including 3D surface profiling using a confocal microscope(VT61000),microhardness measurements via Vickers testing(THV1-MDT),residual stress analysis using X-ray diffraction(X-350A),and phase structure examination via XRD(LabX XRD-6100X).Fatigue tests are performed under axial loading using a servo-hydraulic fatigue machine at room temperature with stress ratios R=0.1 and maximum cyclic stress ranging from 240 MPa to 432 MPa.Fatigue fracture morphology is analyzed using SEM to investigate crack initiation and propagation behavior.Results and Discussions The WGL process substantially enhances the surface characteristics and fatigue performance of the 2519A aluminum alloy specimens.Line roughness(Ra)decreases progressively from 2.551μm(AWJ)to 1.335μm(WGL-3),demonstrating a 47.7%improvement(Fig.4).3D surface profiles(Fig.3)reveale smoother and more uniform morphologies in WGL-treated samples,with the WGL-3 group showing minimal height variation and improved flatness.SEM micrographs(Fig.5)reveal that AWJ-treated surfaces contain distinct microcracks and erosion pits,while WGL-treated surfaces exhibit reduced damage and more compact textures,despite minor peeling observed in WGL-3 due to excessive energy input.Microhardness analysis(Fig.6)indicates that WGL treatment produces significant increases in surface hardness and hardened layer depth.WGL-3 achieves the highest surface hardness at 186.71 HV and a hardened layer extending to 356μm,compared to 160.54 HV and 204μm for the AWJ sample.Residual stress profiles(Fig.7,Table 2)show marked increases in surface residual compression stress(CRS),from 37 MPa(AWJ)to 287 MPa(WGL-3),and deeper residual stress influence zones.The maximum CRS in WGL-3 occurrs at the surface,indicating a surface-concentrated strengthening effect,while the deeper CRS depth confirms the water-constrained energy transfer efficiency.XRD analysis(Fig.8)demonstrates that no new phases emerge during processing;however,(111)diffraction peaks shift to higher angles and broaden after WGL treatment,particularly in WGL-3.This indicates grain refinement,lattice distortion,and high dislocation density—factors crucial for fatigue resistance.These structural modifications correspond with the observed mechanical property improvements.Fatigue testing(Fig.9)demonstrates significant enhancement in fatigue performance through WGL treatment.Under a maximum stress of 312 MPa,fatigue life increases from 4.15×106 cycles(AWJ)to 1.95×107 cycles(WGL-3),representing a 370%improvement.Under high-load(432 MPa)conditions,WGL-3 extends fatigue life by up to 3.77 times.S-N curves for WGL-treated samples consistently shift rightward,confirming enhanced fatigue resistance.SEM fractography(Fig.10)reveals that crack initiation shifts from the surface(AWJ)to subsurface(WGL-1 and WGL-2),and fracture surfaces evolve from coarse,uneven morphologies to smoother,striation-dominated patterns with reduced secondary cracks,particularly in WGL-3.Conclusions WGL treatment effectively reduces surface roughness and micro-defects,with the WGL-3 condition demonstrating a greater than 50%improvement in Ra and Sa parameters compared to AWJ processing.The surface microhardness and compressive residual stress exhibit significant enhancement through WGL treatment.The WGL-3 condition achieves the most substantial improvements,producing the deepest hardened layer(356μm)and highest surface residual stress(287 MPa).The fatigue performance of the alloy improves significantly,with WGL-3 demonstrating the most pronounced enhancement.The treatment delays crack initiation and results in more stable crack propagation characteristics.While WGL presents a promising and thermally safe method for surface strengthening of high-strength aluminum alloys,excessive energy input may induce over-peening effects,potentially leading to surface peeling and stress concentration.Therefore,careful optimization of processing parameters remains essential for achieving an optimal balance between performance enhancement and structural integrity.