OBRABOTKAMETALLOV Vol. 27 No. 2 2025 technology Anumber of works are devoted to ultrasonic SPD [38–47], which leads to a significant reduction in surface roughness, surface hardening and promotes the closure of pores in the subsurface layer. The disadvantage of this method is the difficulties and limitations in the treatment of complex surfaces associated with the inability to bring the indenter of the ultrasonic oscillatory system to hard-to-reach places. Thus, additional research is required to study in more detail the effect of various types of ultrasonic treatment on the properties of surfaces obtained by additive technologies and to optimize the conditions for the treatment of complex products. Based on the above, the purpose of this work is to determine the effect of various types of ultrasonic treatment on the properties of the surface obtained by selective laser melting through comparative tests. To achieve this purpose, the following research objectives are set: – analysis of the main mechanisms of action in ultrasonic treatment methods (CET, CAT, SPD); – studying the dynamics of surface changes using these methods; – studying the micro- and submicrogeometry of the treated surface; – studying the microstructure of the transverse microsection after ultrasonic SPD. Research method Material and sample production The samples for experimental studies were cubes of 10×10×10 mm, made by selective laser melting of Ti-6Al-4V titanium alloy powder with the chemical composition shown in Table 1. Ta b l e 1 Chemical composition of Ti-6Al 4V powder Element Ti Al V Fe Zr Bal. Content, % 89.72 5.3 3.7 0.17 0.04 ≈ 1 This material was chosen for research because it is widely used in aerospace engineering, where the production of complex-shaped parts is particularly promising. Furthermore, after selective laser melting, it exhibits pronounced surface defects, as described previously. The samples were produced at the STANKIN Institute, Department of High-Efficiency Treatment Technologies, using an EOS M280 machine. The powder had a diameter of 40 µm, and the SLM process used a laser beam power of 200 W and a scanning speed of 1,100 mm/s. A total of 25 samples were produced: 5 control samples (without treatment) and 5 samples for each type of treatment under consideration. The treatment schemes are shown in Fig. 2 and Fig. 4. The lateral surface was selected as the surface for study, as it forms complex elements. Fig. 1, a shows a photograph of the surface condition after production, Fig. 1, b shows a transverse microsection illustrating defects. The surface relief is characterized by a sequence of spheres of various diameters. Some of these spheres are the result of spheroidization, while others are partially molten powder or particles of non-molten powder adhering to the surface during the crystallization of the outermost melt tracks. From the perspective of reducing roughness through further treatment, the spheroidization defects are the most challenging. These spheres are formed from molten tracks of liquid metal and, after crystallization, become almost an integral part of the surface. Ultrasonic treatment schemes and equipment Ultrasonic cavitation-erosion treatment (CET), cavitation-abrasive treatment (CAT), and surface plastic deformation (SPD) were used to modify the surface condition. Preliminary experiments on liquid-based CET and CAT of Ti-6Al-4V samples showed that the alloy’s strong surface oxide film results in high cavitation resistance. Consequently, even with prolonged ultrasonic
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