李海洋,赵喆,郑超,季忠,赵国群.激光冲击光整对2024铝合金铣削平面表面质量的影响[J].表面技术,2023,52(9):388-396.
LI Hai-yang,ZHAO Zhe,ZHENG Chao,JI Zhong,ZHAO Guo-qun.Effect of Laser Shock Finishing on the Surface Quality of 2024 Aluminum Alloy with Milled Plane[J].Surface Technology,2023,52(9):388-396 |
| 激光冲击光整对2024铝合金铣削平面表面质量的影响 |
| Effect of Laser Shock Finishing on the Surface Quality of 2024 Aluminum Alloy with Milled Plane |
| 投稿时间：2022-07-29 修订日期：2023-03-21 |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.09.035 |
| 中文关键词: 激光冲击 2024铝合金 表面形貌 表面粗糙度 光斑搭接率 激光能量 |
| 英文关键词:laser shock 2024 aluminum alloy surface morphology surface roughness overlapping rate laser energy |
| 基金项目:国家自然科学基金(52075299，52075298);山东省自然科学基金(ZR2020ME149);山东省重点研发计划(2021ZLGX01) |
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| Author | Institution |
| LI Hai-yang | School of Materials Science and Engineering, Shandong University, Jinan 250061, China |
| ZHAO Zhe | School of Materials Science and Engineering, Shandong University, Jinan 250061, China |
| ZHENG Chao | School of Materials Science and Engineering, Shandong University, Jinan 250061, China |
| JI Zhong | School of Materials Science and Engineering, Shandong University, Jinan 250061, China |
| ZHAO Guo-qun | School of Materials Science and Engineering, Shandong University, Jinan 250061, China |
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| 中文摘要: |
| 目的 减小铝合金铣削平面的表面粗糙度，满足工程应用中对构件高质量表面的需求。方法 通过铣削加工获得3种具有不同初始表面粗糙度的平面试样，试样的Ra分别为1.439、0.614、0.220 μm。采用短脉冲、高功率密度激光对表面进行光整处理，利用激光共聚焦显微镜观察光整后试样的表面形貌，采用粗糙度仪检测试样的表面轮廓和表面粗糙度，分析光斑搭接率和激光能量对铝合金铣削平面表面质量的作用规律。结果 在脉冲宽度为12 ns、波长为1 064 nm、工作频率为1 Hz、光斑直径为2 mm的平顶光束作用下，试样的表面形貌发生重塑。当光斑搭接率为30%、50%、70%时，对于Ra=1.439 μm的试样，在冲击后其表面轮廓变化幅值分别为6.88、6.71、6.20 μm，表面粗糙度变化率分别为−70.8%、−72.9%、−73.2%;对于Ra= 0.614 μm的试样，在冲击后其表面粗糙度变化率分别为−58.0%、−58.8%、−66.1%。当激光能量为1.5、2.5、3.5、4.5 J时，对于Ra=1.439 μm的试样，在冲击后其表面轮廓变化幅值分别为6.92、6.71、5.22、6.18 μm，表面粗糙度变化率分别为−68.1%、−72.9%、−74.6%、−73.8%;对于Ra=0.614 μm的试样，在冲击后其表面粗糙度变化率分别为−49.2%、−58.8%、−54.4%、−58.1%。结论 合理增大光斑搭接率和增强激光能量，能够有效去除铣削刀痕，改善试样表面形貌的均匀性。光斑搭接率和激光能量对表面粗糙度的影响与试样的初始表面粗糙度有关。对于Ra=1.439 μm和Ra=0.614 μm的试样，增大光斑搭接率和增强激光能量均能显著降低其表面粗糙度;对于Ra=0.220 μm的试样，在文中的激光冲击参数范围内均不能有效提高其表面质量。 |
| 英文摘要: |
| Aluminum alloy is widely applied in the field of aeronautics and astronautics because of its light weight, high specific strength and excellent corrosion resistance. The parts made of aluminum alloy are usually processed by milling, and the surface quality after milling is closely associated with the service performance of these parts. Therefore, finishing process is necessary to reduce the roughness and strengthen the mechanical property of milled surface. Laser shock finishing is a novel flexible manufacturing method in which the laser shock wave pressure is employed to cause plastic deformation on the surface and further improve the surface quality. Compared with the traditional finishing process, laser shock finishing takes advantages of superb flexibility, good repeatability, high efficiency and high precision. However, few attempts have been made to study the effect of laser shock finishing on the surface quality of aluminum alloy after milling. In this work, the effect of laser shock parameters on the finishing quality of 2024-T351 aluminum alloy with milled plane was experimentally investigated. The planar milled specimens with three different initial roughness were manufactured through CNC machining center, and the initial Ra was 1.439, 0.614, and 0.220 μm respectively. A laser system with ultrashort pulse and high laser power density was employed to finish the milled plane. After that, a laser scanning confocal microscope was used to observe the surface morphology of specimens after laser shock finishing. Both the surface profile and roughness were measured by a roughmeter. Based on the measurement, the effect of overlapping rate and laser energy on the surface quality of 2024-T351 aluminum alloy with milled plane was evaluated. It was found that the surface morphology of planar milled specimens could be reshaped by the laser in case of pulse width of 12 ns, wavelength of 1 064 nm, working frequency of 1 Hz, spot diameter of 2 mm and flat-topped beam. While the overlapping rate was 30%, 50%, and 70%, for the specimens with Ra of 1.439 μm, the changing amplitude of surface profile after laser shock finishing was 6.88, 6.71, and 6.20 μm, and the changing rate of roughness was −70.8%, −72.9%, and −73.2% respectively. For the specimens with Ra of 0.614 μm the changing rate of roughness after laser shock was −58.0%, −58.8%, and −66.1%. While the laser energy was 1.5, 2.5, 3.5, and 4.5 J, for the specimens with Ra of 1.439 μm the changing amplitude of surface profile after laser shock finishing was 6.92, 6.71, 5.22, and 6.18 μm, and the changing rate of roughness was −68.1%, −72.9%, −74.6%, and −73.8% respectively. For the specimens with Ra of 0.614 μm the changing rate of roughness after laser shock was −49.2%, −58.8%, −54.4%, and −58.1%. It is revealed that both increasing overlapping rate and strengthening laser energy reasonably can effectively remove the milled mark on the surface and improve the uniformity of surface morphology. In addition, the effect of overlapping rate and laser energy on roughness strongly is related to the initial roughness of planar milled specimens. For the specimens with Ra of 1.439 and 0.614 μm, both increasing overlapping rate and strengthening laser energy can significantly reduce the roughness after laser shock. However, for the specimens with initial Ra of 0.220 μm, the surface quality can not be improved under the given laser shock conditions. |
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