OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 3 2024 Conclusion In the course of the research, a technology for forming a promising aluminum alloyAlSi8Mg for selective laser melting and non-spherical powders is developed. The material shows good manufacturability and low powder cost. The technological parameters of melting allow forming a fine structure with low porosity. The mechanism of the influence of the scanning strategy on porosity, surface morphology, relative density and microstructure is studied. The main conclusions are summarized as follows. A specimen was produced from AlSi8Mg powder composition with high relative density of 99.97 % by selective laser melting. The energy density significantly affects the quality of the surface. In this study the energy density of 200 J/mm3 and the specimen formation scanning strategy III when the direction of the laser movement changes by 90° every odd layer (n, n + 2, etc.) and in every even layer (n + 1, n + 3), the direction of the laser beam is parallel to the previous layer, and the track is shifted by a distance of S/2 (∠ 90S/2) are the best parameters of the process allowing to achieve the highest relative density. It is proven that the density of AlSiMg alloy depends on the scanning strategy used. The calculated density of the specimens for scanning strategies I and II was 2.49 g/cm3, and for the specimen obtained using scanning strategy III, 2.5 g/cm3, which corresponds to the density of silumin. Analysis of SEM images and element distribution maps (Al, Si, Mg) of the specimens showed that different strategies for producing specimens do not affect the nature of silicon distribution. Unique grain structure is observed in the finished AlSi8Mg alloy. In the melt pool small grains are located along the boundary, while large grains are in the center. Addition of silicon and high cooling rates are positive conditions for formation of fine grains. References 1. Oliveira J.P., LaLonde A.D., Ma J. Processing parameters in laser powder bed fusion metal additive manufacturing. Materials and Design, 2020, vol. 193 p. 108762. DOI: 10.1016/j.matdes.2020.108762. 2. Kanazawa M., Iwaki M., Minakuchi S., Naoyuki N. Fabrication of titanium alloy frameworks for complete dentures by selective laser melting. Journal of Prosthetic Dentistry, 2014, vol. 112 (6), pp. 1441–1447. – DOI: 10.1016/j. prosdent.2014.06.017. 3. Kotadia H.R., Gibbons G., Das A., Howes P.D. A review of laser powder bed fusion additive manufacturing of aluminium alloys: microstructure and properties. Additive Manufacturing, 2021, vol. 46, p. 102155. DOI: 10.1016/j. addma.2021.102155. 4. Wang Z.H., Lin X., Kang N., Wang Y.F., Yu X.B., Tan H., Yang H.O., Huang W.D. Making selective-lasermelted high-strength Al-Mg-Sc-Zr alloy tough via ultrafine and heterogeneous microstructure. Scripta Materialia, 2021, vol. 203, p. 114052. DOI: 10.1016/j.scriptamat.2021.114052. 5. Geng Y.X., Wang Y.M., Xu J.H., Mi S.B., Fan S.M., Xiao Y.K., Wu Y., Luan J.H. A high-strength AlSiMg1.4 alloy fabricated by selective laser melting. Journal of Alloys and Compounds, 2021, vol. 867, p. 159103. DOI: 10.1016/j.jallcom.2021.159103. 6. Zhang J.L., Gao J.B., Song B., Zhang L.J., Han C.J., Cai C., Zhou K., Shi Y.S.Anovel crack-free Ti-modifiedAlCu-Mg alloy designed for selective laser melting. Additive Manufacturing, 2021, vol. 38, p. 101829. DOI: 10.1016/j. addma.2020.101829. 7. Shah A.W., Ha S., Kim B., Yoon Y., Lim H., Kim S.K. Effect of Al2Ca addition and heat treatment on the microstructure modification and tensile properties of hypoeutectic Al–Mg–Si alloys. Materials, 2021, vol. 14, p. 4588. DOI: 10.3390/ma14164588. 8. Lefebvre W., Rose G., Delroisse P., Baustert E., Cuvilly F., Simar A. Nanoscale periodic gradients generated by laser powder bed fusion of an AlSi10Mg alloy. Materials and Design, 2021, vol. 197, p. 109264. DOI: 10.1016/j. matdes.2020.109264. 9. Bayoumy D., Schliephake D., Dietrich S., Wu X.H., Zhu Y.M., Huang A.J. Intensive processing optimization for achieving strong and ductile Al-Mn-Mg-Sc-Zr alloy produced by selective laser melting. Materials and Design, 2021, vol. 198, p. 109317. DOI: 10.1016/j.matdes.2020.109317. 10. Rao J.H., Zhang Y., Zhang K., Huang A., Davies C.H.J., Wu X. Multiple precipitation pathways in an Al7Si-0.6Mg alloy fabricated by selective laser melting, Scripta Materialia, 2019, vol. 160, pp. 66–69. DOI: 10.1016/j. scriptamat.2018.09.045.
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