OBRABOTKAMETALLOV Vol. 26 No. 1 2024 TECHNOLOGY a b c d Fig. 3. SEM images (a) and distribution maps of the elements Al (b), Si (c), Mg (d), after 1 hour of mechanical activation individual small particles ranging in size from 5 to 20 μm and is also present as a deposit of smaller particles on the surface of aluminum. Silicon is present in the smallest amount in the volume of the powder mixture, as can be seen on the corresponding distribution map (fi gure 3, d). This fact is also confi rmed by the completed elemental energy-dispersive microanalysis. The magnesium content in the volume of the powder mixture does not exceed 1.3 wt. % and 1.5 at. %. At the same time, the aluminum content in the powder composition is 90.3 wt. % and 90.8 at. %, and that of silicon is 8.4 wt. % and 7.7 at. %. The specimens were produced from the composite powder using VARISKAF-100MVS unit. Based on the results of exploratory experiments, the following variable mode parameters were selected for further research: scanning speed: 225, 250, 275, 300 mm/s, scanning step: 0.09, 0.08, 0.07 mm; the constant parameters were as follows: continuous laser radiation power – 90 W, powder layer thickness – 0.025 mm, argon protective environment; the temperature of the working table at the beginning of the SLM cycle was +25 °C. Specimens with a size of 10×10×2 mm were made. At a scanning speed of 300 mm/s, the surface of the specimens showed an increase in porosity, so experiments were not carried out at 350 mm/s. The table presents the photos of the structure of the specimen with minimal porosity of 0.03 %. The specimen was produced under the following SLM mode: P = 90 W; V = 225 mm/s; S = 0.08 mm; h = 0.025 mm; T = 25 C°. Porosity value was found as the average of nine measurements. Porosity was determined in the same way at laser speed V = 250, 275, 300 mm/s. Figure 4 shows the graph of the dependences of the porosity values on the scanning speed for the specimens obtained under the following SLM mode: P = 90 W; h = 0.025mm; T = 25 C°.
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