Laser Etching and Peening for Improved Hydrophobicity and Mechanical Properties of 2024‐T351 Al Alloy

The surface hydrophobicity and mechanical properties of 2024‐T351 Al alloy are improved by laser etching/laser peening without coating (LE/LPwC). The surface morphology, roughness, elemental composition, and surface wettability of the untreated, LE, and LE/LPwC samples are characterized. In addition, the microstructure of the matrix material for each sample is observed, the residual stress and microhardness are measured and analyzed, and the strengthening mechanism of the mechanical properties of the matrix material is explored. The results demonstrate that following LE/LPwC treatment, the Al alloy surface exhibited a micro‐groove micro/nano porous architecture, the surface roughness and oxygen content increased, and the dropper contact angle reached 103°, indicating a hydrophobic state. The droplet contact angle of the LE/LPwC sample reached 161° after the surface energy is reduced by fluorosilane solution modification, which provided the Al alloy surface with beneficial superhydrophobic properties. The grain size of the LE/LPwC sample decreased, accompanied by an increase in the dislocation density. Concurrently, there is an enhancement in both the microhardness and residual compressive stress. The LE/LPwC process achieves synergistic optimization of both hydrophobicity and mechanical properties in the Al alloy, which can effectively facilitate the application of superhydrophobic surface fabrication technology in mechanically demanding aerospace applications.