纳秒激光调控CFRP复合材料表面润湿性及其对胶接性能的影响

Tailoring CFRP composite surface wettability with nanosecond laser and its effect on bonding performance

采用纳秒激光对碳纤维增强树脂基(CFRP)复合材料进行表面预处理,调控其表面成分、粗糙度和表面润湿性,然后采用SEM、接触角测量仪、光学轮廓仪、XPS等表征CFRP复合材料的表面微观形貌、接触角、粗糙度和化学成分,并通过拉伸剪切实验评价和分析激光表面处理对CFRP复合材料胶接强度的影响规律和机制。结果表明:优化激光表面处理参数,可以去除CFRP复合材料表面的环氧树脂胶,调控其表面成分、粗糙度和表面润湿性;与未处理的CFRP复合材料相比,激光表面处理后的CFRP复合材料表面化学成分改变,表面粗糙度有所增加,润湿性提高,胶接强度也增大;与未处理CFRP复合材料相比,激光离焦量分别为5 mm、10 mm和15 mm时,处理后的CFRP复合材料胶接强度分别提高了129.41%、112.13%和105.88%;激光表面处理CFRP复合材料的表面润湿性和表面粗糙度均高于机械处理CFRP复合材料,但激光处理导致的热损伤对胶接强度提高有负面影响。

In this article, nanosecond laser was used to pretreat carbon fiber reinforced plastics(CFRP) composite surface, realizing modifying its surface component, roughness and surface wettability. Then the bonding strengths were tested through tensile shear experiment. The surface morphology, contact angle, surface roughness and chemical component were observed and characterized via SEM, contact angle measuring instrument, optical profiler and XPS. The results indicate that with different laser parameters, the epoxy resin on the surface of CFRP composite can be removed, changing the surface component, roughness and surface wettability, and then improving the bonding strength. Compared with the untreated CFRP composites, after laser surface treatment, the bonding strength of CFRP composites increases with the increase of surface wettability and surface roughness, and also changing with the change of chemical component. On the basis of untreated CFRP composites, when the laser defocus is 5 mm,10 mm and 15 mm, respectively, the bonding strengths are increased by 129.41%, 112.13% and 105.88%, respectively. The surface wettability and surface roughness of laser treated CFRP composites are greater than those of the mechanically-treated CFRP composites. However, the heat damage caused by nanosecond laser treatment has a negative effect on improvement of bonding strength. Therefore, the bonding strength of the nanosecond laser treated CFRP composites are lower than that of mechanically-treated CFRP composites. That is to say, laser treatment process should be furtherly optimized to demonstrate the advantages of laser treatment.