Influence of combined burst-mode ultrashort laser irradiation on surface topography and tribological properties of cemented tungsten carbide

The characteristic heat accumulation within a burst of ultrashort pulses enables the formation of new types of surface alloys. The melt dynamics during irradiation provide the opportunity to change the surface texture in a controlled manner. However, there is still very limited information available on the influence of the topography of solidified melts of these novel surface alloys on the tribological properties of the metal matrix composite (MMC) surface. In this study, the authors report on the use of a burst-mode solid-state laser with an emitting wavelength of 1064 nm and a pulse duration of 10 ps for the surface treatment of the MMC cemented tungsten carbide. This treatment and texturing form a novel surface alloy with different topographies of the solidified melt. The characterization of the generated topographies and their tribological properties is conducted by means of pin-on-disk and nanoindenter hardness measurements of the remelted surfaces. Furthermore, x-ray diffraction analyses provide the basis for the discussion of newly formed phases. The results demonstrate that surface treatment with burst pulses has a significant influence on the tribological properties, which can be manifested in an increase or decrease in the coefficient of friction or wear.