Effects of Laser Microtexturing on the Wetting Behavior of Ti6Al4V Alloy

Abstract

Surface modification procedures by laser techniques allow the generation of specific topographies and microstructures that enable the adaptation of the external layers of materials for specific applications. In laser texturing processes, it is possible to maintain control over the microgeometry and dimensions of the surface pattern through varying the processing parameters. One of the main areas of interest in the field of surface modification treatments is the ability to generate topographies that are associated with specific surface finishes, in terms of roughness, that can improve the manufactured part's functional capabilities. In this aspect, several types of phenomena have been detected, such as the friction and sliding wear behavior or wetting capacity, which maintain a high dependence on surface roughness. In this research, surface texturing treatments have been developed by laser techniques through using the scanning speed of the beam (V s) as a control parameter in order to generate samples that have topographies with different natures. Through assessments of surface finish using specialized techniques, the dimensional and geometrical features of the texturized tracks have been characterized, analyzing their influence on the wetting behavior of the irradiated layer. In this way, more defined texturing grooves has been developed by increasing the V s , which also improves the hydrophobic characteristics of the treated surface. However, due to the lack of uniformity in the solidification process of the irradiated area, some deviations from the expected trends and singular points can be observed. Using the contact angle method to evaluate the wetting behavior of the applied treatments found increases in the contact angle values for high texturing speeds, finding a maximum value of 65.59 • for V s = 200 mm/s.

Assessment the Sliding Wear Behavior of Laser Microtexturing Ti6Al4V under Wet Conditions

“…When V s was increased, an important growth occurred on the contact angle values, raising the hydrophobic behavior trends of the modified surface. This is especially caused by an increase in the compactness of the treated layer as a result of the development of textures with a higher contact area between different phases [19]. This phenomenon is reproduced under all the range of E d analyzed in this work.…”

“…Wear volume is not just affected by the wettability of the texture, but also by V s parameter. This control parameter was related to the thermochemical process that produced the oxidation of the surfaces, the possible changes produced on the microstructure of the layer and the thickness of the affected layer [15,19,36]. This fact confirmed that laser surface processing results in a protective mechanism of the Ti6Al4V against tribological wear effects.…”

“…This kind of techniques represents an essential tool to improve the functional performance of specific alloys in working environments, through the variation of specific features as wetting or tribological behavior [9][10][11][12][13][14][15]. By using laser surface processing procedures regular or random texture patterns can be achieved [13,[16][17][18][19][20][21]. Laser texturing techniques can be used to induce a large variety of topographies in terms of the distribution and geometry of the irradiated pattern being the most common linear, circular and pulses array distributions [13,16,19,21].…”

“…By using laser surface processing procedures regular or random texture patterns can be achieved [13,[16][17][18][19][20][21]. Laser texturing techniques can be used to induce a large variety of topographies in terms of the distribution and geometry of the irradiated pattern being the most common linear, circular and pulses array distributions [13,16,19,21]. Due to this fact, it is known that the geometrical and dimensional characteristics of the generated structures have a direct influence with the contact angle between the liquid and solid phases, resulting in higher or lower water retention capability [13,19,[22][23][24][25][26].…”

“…Based on this background and taking as starting point preliminary studies focused on the water retention of surfaces by microtexturing treatments [19], the aim of this research is to investigate the influence of laser processing parameters on the improvement of tribological wear behavior of Ti6Al4V surfaces under wet conditions. A laser surface treatment using a conventional laser marking system have been presented to develop specific surface patterns of linear tracks on titanium samples.…”