Fabrication of multi-scale periodic surface structures on Ti-6Al-4V by direct laser writing and direct laser interference patterning for modified wettability applications

Abstract

In this work, hierarchical surface patterns fabricated on Ti-6Al-4V alloy combining two laser micro-machining techniques are presented. The used technologies are based on nanosecond Direct Laser Writing and picosecond Direct Laser Interference Patterning. Squared shape micro-cells with different hatch distances were produced by Direct Laser Writing with depths values in the micro-scale, forming a well-defined closed packet. Subsequently, cross-like periodic patterns were fabricated by means of Direct Laser Interference Patterning using a two-beam configuration, generating a dual-scale periodic surface structure in both micro- and nano-scale due to the formation of Laser-Induced Periodic Surface Structure after the picosecond process. As a result a triple hierarchical periodic surface structure was generated. The surface morphology of the irradiated area was characterized with scanning electron microscopy and confocal microscopy. Additionally, static contact angle measurements were made to analyze the wettability behavior of the structures, showing a hydrophobic behavior for the hierarchical structures

Design Rules for Laser‐Treated Icephobic Metallic Surfaces for Aeronautic Applications

“…Both surfaces have pillars with an average depth at the maxima–maxima positions of 1.8 ± 0.25 and 3.0 ± 0.23 µm, correspondingly. As reported for Ti64 surfaces treated with ps‐DLIP, [ 38 ] the laser‐treated samples show additional surface features, which can be identified as low spatial frequency LIPSS (LSFL) with a spatial period of ≈400 nm. High spatial frequency LIPSS (HSFL) can be observed in perpendicular direction to the LSFL (inset in Figure 1b).…”

“…Different laser processes and pulse durations have been used to tune the surface wettability of metals by generating hierarchically structured superhydrophobic surfaces. [ 35–38 ] Many of these works suggest that such surfaces can be also used for icephobic applications. [ 39–41 ] In a research previously published, it was shown that Ti6Al4V (Ti64) offers a robust substrate for the laser‐generated features compared to Aluminum Alloy 2024 (AA2024), since these features providing the support for the Cassie–Baxter state remain unchanged on Ti64 after 16 icing/deicing cycles, while are partially destroyed on the AA2024.…”

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

“…electrodeposition step was used, which led to the deposition of spherical nickel droplets on the tips of the micro-textures as shown in Figure 4 [46]. Finally, an innovative method to create multi-scale surface textures is to combine two different laser processes, namely DLW and DLIP [76,77]. Thereby, the bigger surface textures are created by DLW and the smaller textures by DLIP.…”

“…Ahmmed and Kietzig used a femtosecond Ti:sapphire laser system with a wavelength of 800 nm and a pulse duration <85 fs to fabricate multi-scale textures on copper [81]. The laser inscribed primary pattern demonstrated a width of 14-80 µm and a depth of 60-130 µm whereas Finally, an innovative method to create multi-scale surface textures is to combine two different laser processes, namely DLW and DLIP [76,77]. Thereby, the bigger surface textures are created by DLW and the smaller textures by DLIP.…”

Holographic Fabrication of 3D Nanostructures

“…The combination of HL and micropatterning methods, such as photolithography and direct laser writing, [129][130][131][132] can further provide multiscale structures having micro-and nanostructural features. The integration of HL-featured 3D nanostructures into microfluidic channels has produced optofluidic sensing platforms that embed optical sensing units, 3D passive mixers, and filters.…”