Wettability Control on YW2 Cemented Carbide Surface by Femtosecond Laser Irradiation

Abstract

The surface wettability control of cemented carbide tools is beneficial to the improvement of tool life and surface quality of workpieces in wet cutting. To clarify the correlation between the surface topography and wettability, squared microdimples are fabricated on the cemented carbide surface using a femtosecond laser. The dependencies of the side length, the depth, and the distribution density of squared microdimples on the surface topography and contact angle are studied. As the average laser power, and the number of scanning passes, increase, both the side length and depth of the squared microdimples increase. The contact angle decreases from hydrophilic to superhydrophilic. Moreover, the roughness height parameters have a great influence on the surface wettability, the larger the surface arithmetic average height, the smaller the kurtosis, the larger the skewness, and the better the hydrophilicity. The results of the scanning electron microscope (SEM) and energy‐dispersive spectrometer (EDS) reflect that the changes in the micro–nano protrusions, carbon, and oxygen elements cause deviation between the calculated contact angle and the actual contact angle. The friction coefficient of textured tools is lower than that of untextured tools at high sliding speed. Reasonable design of surface texture accurately controls surface wettability.