OBRABOTKAMETALLOV TECHNOLOGY Vol. 26 No. 4 2024 The structure of the surface layer also includes a melting zone, a heat-aff ected zone, and the base metal (Fig. 7, a-d). Within the materials of these zones, there are pores (1 in Fig. 7, e) and discontinuities (2 in Fig. 7, g). However, the molten metal zone is signifi cantly smaller, with a thickness not exceeding 100-200 μm in the central part, while the heat-aff ected zone is only weakly defi ned (Fig. 7, a-d, Fig. 8, a). The microhardness values in the surface layers show minimal variation, which can be attributed to the high thermal conductivity of the material and rapid cooling. Consequently, energy dispersive spectroscopy (EDS) analysis indicates that no qualitative changes in the phase composition occur within the material (Fig. 8, b, c). The primary phase consists of a solid solution of Cu(Al) and the β’-phase (needle-like Cu3Al present between the grains of the solid solution). In the melting and heat-aff ected zones, only changes in the volume fraction and concentration of these phases can be identifi ed (Fig. 7, c, f). Additionally, secondary phases appear as particles of Cu3Al throughout the material. The high thermal conductivity of the material leads to lesser structural changes in the near-surface zone compared to the aluminum alloy, while also resulting in a larger proportion of material not displaced from the cutting zone in the lower part of the cut, as illustrated in Fig. 2, c. Overall, based on the analysis of geometric distortion and structural changes in the material for plates of this size, the quality of the cut can be considered acceptable. The morphology of the cut surface of the Ti-5Al-5Mo-5V titanium alloy in the upper, lower, and central regions is fairly consistent (Fig. 9, a-c). Unlike copper and aluminum alloys, the surface topography in this case exhibits only minimal traces of the material following the contour of the tool. However, there are HAZ FZ BM BM BM HAZ FZ FZ HAZ FZ FZ HAZ BM FZ а b c d e f g Fig. 7. Macrostructure (a), images of the microstructure obtained by optical (b–d) and scanning electron (e–g) microscopy of a specimen of bronze Cu-9 Al-2 Mn
RkJQdWJsaXNoZXIy MTk0ODM1