Objective The GH3044 alloy is promising for diverse aerospace applications because of its exceptional physicochemical properties. However, inherent surface defects, such as elevated roughness and oxidized layers, are incurred during processing and manufacturing. These defects significantly compromise the reliability and durability of the resulting products, thereby constraining their scope of application. This study introduces a laser- assisted jet electrochemical polishing method that integrates laser polishing and electrochemical jet polishing to leverage the synergies of both techniques to achieve high- quality and efficient polishing of the GH3044 alloy. The primary objective of this study is to experimentally polish the surface of a GH3044 alloy using laser- assisted jet electrochemical polishing technology and to explore the impacts of different process parameters (laser power and scanning time) on the surface roughness. Concurrently, a detailed analysis of the surface morphology, microstructure, and phase changes of the polished samples is conducted. This investigation aims to offer novel insights and empirical support for the implementation of laser- assisted jet electrochemical polishing technology on sizable high- temperature alloy workpieces to ultimately enhance the workpiece surface quality and extend the operational lifespan. Methods In this study, the surface of the GH3044 alloy, which possesses an original roughness of 680 nm, is subjected to preliminary spot polishing and subsequent line- scan polishing. By employing laser confocal technology, a comprehensive analysis of the three-dimensional morphology, depth, and roughness is conducted. The primary objectives are to examine the influence of laser parameters on the surface morphology and roughness and to explore the impact of varying the scanning times during line scanning processing. This study aims to identify the optimal polishing parameters. Subsequently, the substrate surface is scanned and polished at the optimized scanning speed. Surface characterization before and after polishing, along with an examination of the changes in the surface micromorphology, physical phase, and elemental composition, is performed using scanning electron microscope (SEM), energy spectrum analyzer (EDS), electron backscattering diffraction (EBSD), X-ray photoelectron spectrometer (XPS), and X-ray diffractometer (XRD). Building on this, a detailed discussion on the mechanism of laser- assisted jet electrochemical polishing is presented in this study. Results and Discussions This study investigates morphologies and roughness after laser- assisted jet electrochemical spot polishing at different laser powers. The experimental results show that as the laser power increases, the roughness tends to increase and then decrease (Fig. 2), and it reaches its lowest value when the laser power is 30 W. Subsequently, line scanning polishing is investigated at different scanning times, and the results show that the polishing reaction is insufficient at low scanning times and has a poor effect. The melting phenomenon owing to heat accumulation at high scanning times affects the polishing effect (Fig. 4), and the best polishing effect is achieved at 15 scan times. On this basis, face polishing is investigated under different scanning speeds, and it is found that lap traces gradually disappear with the increase in scanning speed (Fig. 5). Mirror-like face polishing is ultimately achieved by optimizing the polishing process, and the roughness is reduced to 130 nm (Fig. 6). Comparative SEM and EDS analyses of the polished surfaces show that the laser successfully removes insoluble tungsten and its insoluble compounds, through the synergistic effect of high energy and electrochemistry, which improves the surface quality. XPS analyses further confirm that the contents of Ni, W, and their oxides decrease while the contents of Cr and its oxides increase after the polishing process (Fig. 10). Comparative EBSD and XRD analyses of the substrate surfaces before and after polishing show that polishing does not significantly change the crystal structure or matrix phase of the substrates (Figs. 8 and 11). Conclusions In this study, the surface of a GH344 alloy is subjected to laser- assisted jet electrochemical polishing. Initially, the impact of various laser powers on the spot polishing morphology is analyzed. Subsequently, the study explores the effects of different scanning times on the morphology and roughness during line- scanning polishing, as well as the consequences of different scanning speeds on the face scanning outcomes, are discussed. Based on these findings, the laser- assisted jet electrochemical polishing process is optimized, leading to the successful fabrication of a mirror-like surface with a reduced roughness of 130 nm. The mechanism of laser- assisted jet electrochemical polishing is comprehensively explored through comparative analyses of the microscopic morphologies, physical phases, and elemental compositions before and after polishing. The investigation reveals that the laser contributes to surface polishing through two key aspects: enhancement of the ion transport rate, which in turn accelerates the dissolution of the passivation film, and the dissolution of insoluble compounds. These critical elements collectively underscore the efficacy of laser- assisted jet electrochemical polishing, significantly improving both the speed and quality of the polishing process.
