航空铝合金表面涂层无损激光清洗研究

激光清洗以绿色、安全、便于控制等优点，在航空航天、电子、交通等领域有着重要的应用价值。采用纳秒脉冲激光清洗航空2A12铝合金表面TB06-9涂层，研发了一种新型的两步法无损激光清洗工艺。运用扫描电子显微镜、能谱仪，超景深三维显微镜和万能电子实验机等分析激光清洗涂层。结果表明，第一步采用单次激光清洗，随激光功率的增加，试样表面涂层逐渐减少裸露出氧化层及基材。激光功率为40 W时氧化层保留完好，功率为45 W时氧化层开始出现损伤，随着功率的增加，损伤逐渐增多。最终确定第一步优化参数为激光的频率为20 kHz，功率为40 W，扫描速度为1040 mm/s，线间距为0.052 mm。第二步在第一步的基础上进行多次清洗，获得的优化参数为激光频率为1000 kHz，功率为80 W，扫描速度为690 mm/s，线间距为0.034 5 mm。两步法激光清洗试样的表面与原始试样表面形貌相似，表面显微硬度及抗拉强度基本保持一致，较好地保留了材料的原有力学性能。

Study on nondestructive laser cleaning of aviation aluminum alloy surface coating

The laser cleaning has some advantages as non-pollution, safety and controllability, which has significant applications in aerospace, electronic field and transportation. The nanosecond pulsed laser was used to clean TB06-9 coating on the surface of aviation 2A12 aluminum alloy. A novel two-step nondestructive laser cleaning process was developed. Scanning electron microscope, energy dispersive spectrometer, ultra depth of field three-dimensional microscope and universal electronic testing machine are applied to investigate laser cleaning coating. The results show that, the first step is to use a laser cleaning, with the increase of the power, the coating on the sample surface decreases gradually, and the oxide layer and substrate are exposed. When the laser power is 40 W, the oxide layer is well preserved. When the laser power is increased to 45 W, the oxide layer begins to be damaged, with increase of the laser power, the damage of oxide layer gradually increased. The optimization parameters of the first step are the laser frequency of 20 kHz, power of 40 W, scanning speed of 1 040 mm/s and line spacing of 0.052 mm respectively. The second step is to carry out multiple cleaning based on the first step. The second parameters are laser frequency of 1000 kHz, power of 80 W, scanning speed of 690 mm/s, line spacing of 0.034 5 mm respectively. The surface morphology of sample by two-step laser cleanning samples is similar to that of the original samples, and the surface microhardness and tensile strength of the samples remain consistent. The mechanical properties of the material are well maintained.