Effects of Laser Processing Parameters on Texturized Layer Development and Surface Features of Ti6Al4V Alloy Samples

Abstract

Surface engineering is widely used in different areas, such as the aerospace industry or the biomechanical and medical fields. Specifically, laser surface modification techniques may obtain specific surface finishes for special applications. In texturing laser procedures, the control of processing parameters has a great influence on the geometry and characteristics of the treated area. When these processes are carried out on titanium alloys, thin oxide layers are usually developed on the irradiated surface, formed through the thermochemical combination of vaporized material with atmospheric oxygen in the air. In thermal oxidation treatments of Ti6Al4V, the highest concentration of oxides is mainly composed by rutile (TiO 2 ), producing surface property modifications such as hardness, among others. In this research, a thermochemical oxidation of Ti6Al4V alloy has been performed through laser texturing, using laser scanning speed (V s ) and pulse rate (f ) as process control variables, and its influence on the beam absorption capacity of the modified layer have been analyzed. Combined evaluations of microgeometrical features and mechanical properties, such as hardness, verified that, by means of laser texturing treatments, the ability to generate specific topographies and increase the initial hardness of the alloy is obtained. The most advantageous results for the increase of hardness by thermochemical oxidation have been detected in low scan speeds of laser beam treatments, resulting in an increase of approximately 270% using a scanning speed of 10 mm/s. On the other hand, a dependence between roughness values, in terms of R a and R z , and the energy density of pulse (E d ) has been observed, showing higher values of roughness for a 17.68 J/cm 2 energy density of pulse.

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

“…This singular point is caused as a result of the Ti cooling process; the Ti cooled down at the top of the surface obtruding the laser grooves and producing a smother surface. This obstruction is mainly due to a solidification stage in the surface section of vaporized material from the bottom of the textured groove [37].…”

“…The use of conventional laser marking systems for the textures development, usually rejected for this purpose due to their requirement of use in pulse mode, imply a high understanding of the influence of laser processing parameters on the resulting texture features. For linear textures, energy density of pulse (E d ) and scanning speed of the beam (V s ) are shown as two of the most relevant parameters involved in the size and geometrical properties of the laser grooves [35][36][37][38].…”

The Tribocorrosion and Corrosion Properties of Thermally Oxidized Ti6Al4V Alloy in 0.9 wt.% NaCl Physiological Saline

“…Surface modification treatments are the effective solutions to improve the surface properties of titanium. Many surface modification methods such as thermal oxidation [6][7][8][9][10][11][12], physical vapor deposition (PVD) [13][14][15][16], chemical vapor deposition (CVD) [17], nitriding [18], oxidizing [19], sol-gel technology [20], and laser surface modification [21,22] have been proposed. Among them, the thermal oxidation treatment is more convenient, economical, and effective in preparing thick, highly crystalline and in situ grown films than the others.…”

Effects of Laser Microtexturing on the Wetting Behavior of Ti6Al4V Alloy

“…Although there are a wide range of modification treatments by chemical and mechanical procedures to adapt the surface to specific conditions, some treatments such as knurling can generate mechanical stress, and in other cases surface contamination, or result in variations of the properties in the inner layers of the alloy. In this aspect, surface texturing treatments using laser techniques allow the generation of topographies with microgeometry, and properties that are adapted to specific working conditions, without affecting the deeper layers of the material [14,[16][17][18][19][20][21][22][23][24][25][26].…”