The effect of surface texturing on the laser-induced wetting behavior of AlSi5 alloy on Ti6Al4V alloy

Due to the shorter heating time and strongly nonisothermal nature of laser-heating, laser-induced wetting behavior exhibits a huge difference when compared to isothermal wetting. In this study, the laser-induced wetting behavior of AlSi5 alloys on Ti6Al4V substrates with various microtextures was investigated. The role of microtexture in wetting was evaluated using interfacial structures, surface energy, and thermodynamics. The results showed that the laser-induced wetting behavior on untextured Ti6Al4V was dominated by adsorption/desorption and the surface textures changed the dominant limiting factors to diffusion during the early wetting process (stage III-1). After surface texturing, the diffusion of Ti atoms was promoted at the interface, while texturing had a limited effect on the types of intermetallic compounds. The surface energy of textured substrates increased, which was beneficial for wetting. In addition, microtextures led to the generation of energy barriers in the perpendicular direction while affording promotion in the parallel direction. This led to the distortion and stretching of droplets, resulting in anisotropic wetting behavior. The wetting behavior was determined by the synergistic effects of the reaction, surface energy, and thermodynamic driving force. Wettability was promoted only for a groove distance larger than 0.25 mm.