OBRABOTKAMETALLOV TECHNOLOGY Vol. 26 No. 1 2024 a b Fig. 6. Microhardness distribution over the AlSiMg specimen: in the long section of the specimen (a), in the cross section of the specimen (b) a b Fig. 7. SEM images of specimens before annealing (a), after annealing (b) Analysis of the completed studies shows that powder mixing in the process of its mechanical activation contributes to the creation of bulk samples using selective laser melting with uniform distribution of powder elements (aluminum, silicon and magnesium). Figure 6 presents the results of microhardness tests. The microhardness was measured at ten points in the longitudinal and cross sections of the specimen. The tests show that the specimen has an average microhardness value of 1,291 MPa in the longitudinal section, and that of 1,243 MPa in the cross section. The deviations of the values do not exceed 5 %. The modes were selected and the specimens were annealed at a temperature of 400 ºC for 5 hours to reduce residual stresses. SEM images of the annealed specimens show that the surface is characterized by a uniform morphology without visible defects (fi gure 7). Annealing of the specimens leads to densifi cation of the surface structure of the specimens. Figure 8 shows SEM images and distribution maps of elements (Al, Mg, Si) of the specimens obtained after annealing. Aluminum and magnesium are distributed uniformly in all specimens. Silicon in the specimens is distributed in the form of small particles with the size of less than 5 μm.
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