Laser cladding was used to prepare three composite coatings, i.e., Inconel 718 nickel-based superalloy (IN718), IN718-50 wt.% WC created by adding tungsten carbide (WC) particles and IN718-50 wt.% WC assisted by ultrasonic vibration. The phase composition, microstructure evolution, microhardness, residual stress and tribological properties of the three coatings were studied. The addition of WC enhances hardness and improves tribological properties, but also causes aggregation and considerable formation of carbides associated with rough structure. Ultrasonic vibration greatly refines the solidification microstructure, as it can break the growing dendrites, reduce the aggregation of reinforced particles and refine solidified structure. The average microhardness of the latter two composite coatings was increased by 36.37% and 57.15%, respectively, compared with the first IN718 coating, and the last composite coating (ultrasonic assistance) had the lowest COF (0.494). The WC particles and refined carbides converted the wear mechanism from adhesive wear to abrasive wear. In addition, the resultant stress on the surface of the composite coating roughly doubled after adding 50 wt.% WC, and only increased by 49.53% with ultrasonic treatment. The simulation results indicate that acoustic cavitation mainly occurs in the middle and bottom of the molten pool and proper frequency ultrasonic is conducive to the generation of the cavitation effect.

Electrochemical discharge machining (ECDM) and laser machining are emerging nontraditional machining technologies suitable for micro-processing of insulating and hard-brittle materials typified by glass. However, poor machinability of glass is a major constraint, which remains to be solved. For the micro-grooves processed by ECDM, the bottom surface is usually uneven and associated with protrusion structures, while the edges are not straight with obvious wave-shaped heat-affected zones (HAZs) and over-cutting. Besides, the cross section of the micro-grooves processed by the laser is V-shape with a large taper. To solve these problems, this study proposed the laser-assisted ECDM for glass micro-grooving, which combines ECDM and laser machining. This study compared morphological features of the single processing method and the hybrid processing method. The results show that ECDM caused cylindrical protrusions at the bottom of the microgrooves. After processing these micro-grooves by laser, the cylindrical protrusions were removed. However, the edge quality of the microgrooves was still poor. Therefore, we used the laser to get microgrooves first, so we got micro-grooves with better edge quality. Then we use ECDM to improve the taper of microgrooves and the cross-sectional shape of the microgrooves transformed from a V-shape to a U-shape.