Fabrication of Papillary Microstructure Surfaces Using Laser Shock Imprinting
摘要
Papillary microstructure has been widely applied in the fields of self-cleaning, anti-corrosion, drag reduction, moisture resistance, etc. In this work, papillary microstructure was fabricated on the surface of aluminum foil by laser shock imprinting. Firstly, a micro-hole array was fabricated on the surface of A5052 aluminum alloy using laser etching to serve as a micro-mold. Then, micro-hole structures on the surface of the micro-mold were replicated onto the workpiece surface through laser shock imprinting to form papillary microstructures. The results indicate that a multi-layered wrinkled structure appears in the side area of individual papillary microstructures. This structural change is closely related to the deformation mode of the material. The effects of workpiece thickness, (20 μm,30 μm,40 μm and 50 μm), laser shock energy, (835 mJ, 1020 mJ, 1200 mJ, 1380 mJ, 1550 mJ and 1690 mJ) and the number of laser shocks, (1, 2, 3 and 4) on the surface morphology of the papillary microstructures were explored. It was found that the above process parameters significantly affect the forming height of the structures and the demolding effect. After optimization experiments, the optimal process parameters were obtained under workpiece thickness of 30 μm, shock energy of 1550 mJ, and three shocks. The surface hydrophobicity is positively correlated with the height of the microstructures, but the enhancement effect of the papillary microstructures on hydrophobicity is limited, with the maximum contact angle reaching 109°. The surface wettability conforms to the Wenzel model. This study improved the structural morphology and surface properties of aluminum foil by adjusting process parameters, providing a method for the precise manufacturing of papillary microstructures.