| 引用本文: | 冯杰才,李诚,王星,姜梦,杜长林,徐聪聪,章易镰,田应仲.航天铝合金表面脉冲激光毛化工艺及其胶接性能[J].中国表面工程,2024,37(3):67~77 |
| FENG Jiecai,LI Cheng,WANG Xing,JIANG Meng,DU Changlin,XU Congcong,ZHANG Yilian,TIAN Yingzhong.Nanosecond-laser Texturing of Aerospace Aluminum-alloy Surface and Its Bonding Properties[J].China Surface Engineering,2024,37(3):67~77 |
|
| |
|
|
| 本文已被：浏览 1417次 下载 1014次 |
码上扫一扫！ |
|
|
| 航天铝合金表面脉冲激光毛化工艺及其胶接性能 |
|
冯杰才1，李诚1，王星1，姜梦2，杜长林3，徐聪聪3，章易镰1，田应仲1
|
|
1.上海大学机电工程与自动化学院 上海 200444 ；2.哈尔滨工业大学先进焊接与连接国家重点实验室 哈尔滨 150001 ；3.上海航天动力技术研究所 上海 201100
|
|
| 摘要: |
| 传统的铝合金表面处理技术存在污染环境、损伤铝合金基体和加工质量不一致等问题。激光束能量精确可控，可在保证满足工业生产要求的前提下减少对环境的污染，且易于实现自动化。航空发动机制造过程中需要采用金属-粘接剂-金属连接，为提高其胶接强度需要对金属进行表面毛化处理。通过在 LY12CZ 铝合金表面进行纳秒激光毛化，探讨纳秒激光脉冲能量、脉冲频率、脉冲宽度等工艺参数对微孔直径、深度、分布形式等形貌的影响规律，并分析铝合金表面激光烧蚀微孔成形机理及其胶接性能的强化机制。研究表明，当脉冲能量增大时，微坑深度和孔径逐渐增加。当脉冲宽度在 20~120 ns 时增大或脉冲频率在 10~90 kHz 时增大，会导致孔径和孔深增大。当脉冲宽度大于 120 ns 时增大，孔深会减少，孔径会缓慢上升后缓慢减小。当脉冲频率大于 70 kHz 时增大，孔深和孔径会增大。熔融物在 Marangoni 对流作用下形成火山口状表面微结构。 微孔直径较大、深度较深，微孔间距较密集且微孔外部形状呈现火山状的微结构利于胶接剂的渗入，形成“钉扎”作用，可提高铝合金胶接剪切强度至 16.77 MPa，满足工业生产要求的 10 MPa，推荐的工艺参数是激光脉冲能量为 1.8 mJ、脉冲频率为 70 kHz、脉宽为 240 ns、烧蚀次数为 5 次、微孔间距为 100 μm。研究结果可为 LY12CZ 铝合金表面高质量的纳秒激光毛化提供参考。 |
| 关键词: 激光材料加工 铝合金 工艺参数 胶接 形貌 |
| DOI：10.11933/j.issn.1007-9289.20230925002 |
| 分类号:TG178 |
| 基金项目:国家重点研发计划（2023YFB3307700）；先进焊接与连接国家重点实验室开放课题研究基金（AWJ-22M02） |
|
| Nanosecond-laser Texturing of Aerospace Aluminum-alloy Surface and Its Bonding Properties |
|
FENG Jiecai1，LI Cheng1，WANG Xing1，JIANG Meng2，DU Changlin3，XU Congcong3，ZHANG Yilian1，TIAN Yingzhong1
|
|
1.School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200444 , China ；2.State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 , China ；3.Shanghai Space Propulsion Technology Research Institute, Shanghai 201100 , China
|
| Abstract: |
| Owing to the development of aerospace technology, conventional aluminum-alloy surface-treatment technology can no longer satisfy the demands of industrial production for environmental protection and strength consistency. In this regard, nanosecond-laser texturing is an ideal surface-treatment technology that offers the advantages of high processing consistency, zero environmental pollution, and no damage to the processing substrate. However, studies regarding the nanosecond-laser texturing of LY12CZ aluminum alloy to enhance bonding performance are few, and the law of process parameters on micropore formation remains unclear. Therefore, the effects of process parameters on the micro-morphology of aluminum alloy are investigated and the relationship between the bonding-performance-enhancement mechanism and micro-morphology is determined. Specifically, a YLPN-2-20x500-300-5M nanosecond pulse laser is used to laser process a 25 mm×15 mm aluminum-alloy sample. The single-factor-analysis method is adopted to investigate the effects of laser energy (E), laser pulse width (τ), and laser frequency (f) on the morphology of micropores. Laser texturing is performed under a hole spacing of 100 μm, a marking speed of 40 mm / s, and a jump speed of 5 mm / s. E, τ, and f are varied separately to observe their effects on the surface morphology of micropores under a metallographic microscope. A three-dimensional profilometer is used to inspect the processed samples, and the diameter and depth of the micropores are recorded. The analysis software SensoVIEW is used to obtain the average results and construct a graph showing the effects of E, τ, and f on the hole diameter and depth. The formation rules and mechanisms of the micropores are analyzed based on observation results. The tensile shear strength of the sample is measured in accordance with GB / T7124-2008. The tensile shear strength of adhesives (rigid material to rigid material) is determined, and the average results are obtained. The optimal processing parameters are selected after comparing the shear strength, and the relationship between the micro-morphology and shear strength is analyzed. The result shows that E is the main factor affecting the surface microstructure of aluminum alloys. As E increases, the diameter and hole depth increase gradually. When τ is 20–120 ns or the pulse frequency is increased to 10–90 kHz, the hole diameter and depth increase. When τ exceeds 120 ns and increases, the hole depth decreases, whereas the hole diameter increases and then decreases gradually. When f increases above 70 kHz, the hole depth and diameter increase. Meanwhile, when lower E and τ values or higher f values are selected, the aluminum alloy in the laser-processing area flows from the edge to the center of the molten pool. This causes a buildup of molten metal, thus forming in a bulge in the center of the pool. After the aluminum alloy solidifies, a Mexican-hat shape with a convex center and concave edges is formed on the aluminum-alloy specimen. Its hole depth and diameter are small, thus rendering the adhesive’s bonding effect unsatisfactory. Consequently, the bonding performance of the aluminum alloy is subpar. When the appropriate E, τ, and f are selected, the aluminum alloy in the laser-processing area forms a crater-like microstructure owing to Marangoni convection. The micropores exhibit large diameters, large depths, small micropore spacings, and a volcano-like microstructure around the micropores, thus facilitating the penetration of the adhesive and resulting in a “pinning” effect. Consequently, the shear strength of the aluminum-alloy bonding increases to 16.77 MPa, which satisfies industrial production requirements (10 MPa). The recommended process parameters are as follows: laser pulse energy, 1.8 mJ; pulse frequency, 70 kHz; pulse width, 240 ns; ablation times, 5; and micropore spacing, 100 μm. The results of this study serve as useful reference for the high-quality nanosecond laser texturing of LY12CZ aluminum-alloy surfaces. |
| Key words: laser materials processing aluminum alloys process parameters bonding morphology |
|
|
|
|
