OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 The regularities of the structure formation of specimens when printing with EBAM and WAAM technologies are similar to SLM technology. The diff erence is observed mainly in the sizes of phase components. The scanning electronmicroscopy (SEM) photographs of the surface of the printed Inconel 625 specimens are shown in Figure 3. As in other studies [2, 4, 5, 7], fi ne micron-sized particles were often observed in the surfaced material. Considering the particle size of the phase constituents, its quantitative chemical analysis can be diffi cult due to the XRD signal emanating from the matrix material. The chemical composition of the fabricated material (Table 2) is largely similar to that of the wire used for surfacing, except for elements such as iron and aluminum, the content of which was lower. The particles marked as 3 in Figure 3 showed more Nb, Mo, Ti and C (Table 2). This indicates the presence of MC carbides. A similar situation was also observed in Inconel 625 alloy fabricated by additive manufacturing method by the authors of [2, 4, 7]. The phase marked as point 2 had elevated amounts of Ni, Nb, Cr and Mo without the presence of carbon (Table 2). This indicates the presence of intermetallic phases. a b Fig. 3. SEM of specimens obtained using various additive technologies: a – horizontal specimen obtained using EBAM technology; b – horizontal specimen obtained using WAAM technology Ta b l e 2 Chemical composition of the manufactured material Study area from Figure 3, % Ni Cr Nb Mo Si Fe Al Ti C 1 64.0 22.3 1.1 4.2 0.7 1.3 0.1 0.1 6.2 2 2.7 3.5 7.2 0.5 – 0.7 – 48.1 37.3 3 38.5 21.6 16.7 8.9 4.1 0.7 0.2 0.2 9.1 The microhardness of the blanks was determined by the Vickers method at a load of 1 kgf with a dwell time of 10 s, as the average of twenty points at diff erent locations (Figure 4). The analysis of microhardness indices (Table 3) shows that the hardness of vertical specimens is lower than that of horizontal specimens. Both for specimens obtained by EBAM technology and for specimens obtained by WAAM technology, this discrepancy is about 3.5 %. It is also evident from the data obtained that the dispersion of hardness values for vertically orientated specimens is signifi cantly higher than for horizontally orientated specimens. This can be explained by a smaller temperature gradient during the printing process. For horizontal specimens, heat dissipation is more intensive, which leads to the formation of more signifi cant temperature gradients and the formation of a less homogeneous structure. This is consistent with the data of the microstructure analysis of the specimens. In vertically oriented specimens more homogeneous structure is formed; these specimens have fewer pores, fewer inclusions of intermetallic compounds in comparison with horizontally oriented specimens.
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