Simultaneous Micro-Structuring and Surface Smoothing of Additive Manufactured Parts Using DLIP Technique and Its Influence on the Wetting Behaviour

Abstract

It is well known that the surface topography of a part can affect its function as well as its mechanical performance. In this context, we report on the surface modification of additive manufactured components made of Titanium 64 and Scalmalloy®, using Direct Laser Interference Patterning technique. In our experiments, a nanosecond-pulsed near-infrared laser source with a pulse duration of 10 ns was used. By varying the process parameters, periodic structures with different depths and associated roughness values are produced. Additionally, the influence of the resultant morphological characteristics on the wettability behaviour of the fabricated textures is investigated by means of contact angle measurements. The results demonstrated a reduction of the surface roughness of the additive manufactured parts (in the order of some tens of micrometres) and simultaneously the production of well-defined micro-patterns (in the micrometre range), which allow the wettability of the surfaces from 26° and 16° up to 93° and 131° to be tuned for Titanium 6Al 4V and Al-Mg-Sc (Scalmalloy®), respectively.

Fabrication of Water‐ and Ice‐Repellent Surfaces on Additive‐Manufactured Components Using Laser‐Based Microstructuring Methods

“…This can be explained by the different material properties (e.g., thermal conductivity) of titanium and aluminum alloys, which affect the formation of the periodic structures. [ 23 ]…”

“…The reason for taking the measurements after this period of time was because previous studies had already shown that the WCA significantly increases after the laser process until an equilibrium state is reached due to deposition from carbon on the surface from ambient air. [ 23 ] The diagrams include the obtained results with (orange area) and without (blue area) the application of Mecasurf for all surface conditions. The application of Mecasurf allows to elucidate the effects only related to surface topography, as in this case all samples have exactly the same surface chemistry.…”

“…Fundamental parameters of the (single) ns‐DLIP process were chosen from a parameter screening, which was already performed and published in a previous article. [ 23 ]…”

“…This can be explained by the different material properties (e.g., thermal conductivity) of titanium and aluminum alloys, which affect the formation of the periodic structures. [23] The resulting textured surface from the ns-DLIP þ ps-DLW treatments, shown in Figure 2f, also indicates a distinct texture with different characteristics compared with the ns-DLIP þ ps-DLIP-treated specimen. In this case, the topography shows hills and valleys with repetitive distances in xand y-directions, which are in agreement with the expected spatial period of the ns treatment (Λ 1 ¼ 21 μm) as well as the hatch distance used in the ps-DLW process step (Λ 2 ¼ 20 μm).…”

“…Fundamental parameters of the (single) ns-DLIP process were chosen from a parameter screening, which was already performed and published in a previous article. [23] After the ns-DLIP process, a second treatment was performed to create a multiscale surface texture. Two different lasertexturing techniques were considered in this case, DLIP treatment with ps pulses (ps-DLIP) or DLW process also using ps pulses (ps-DLW).…”