OBRABOTKA METALLOV

Introduction. The development of additive technologies is aimed at the synthesis of new powder compositions for selective laser melting plants, the study of the effect of mode parameters on the stable quality of products. The purpose of this work is to study the effect of the scanning strategy on the microstructure, elemental composition, porosity and density of specimens obtained by selective laser melting from non-spherical powders (Al — 91 wt. %, Si — 8 wt. %, Mg — 1 wt. %), subjected to special preparation to determine the optimal conditions for selective laser melting. The research methods are methods of X-ray diffraction and X-ray phase analysis, transmission electron microscopy. The paper examines specimens formed using four different scanning strategies. Results and discussions. A promising aluminum alloy AlSi8Mg is developed for selective laser melting. The material has good manufacturability and low powder cost. The technological parameters of melting make it possible to form a thin structure with a low level of porosity. The mechanism of influence of the scanning strategy on porosity, surface morphology, relative density and microstructure is investigated. A specimen from the AlSi8Mg powder composition with a high relative density of 99.97 % is produced by selective laser melting with an energy density of 200 J/mm³, a specimen scanning circuit when the direction of laser movement changes by an angle of 90° each odd layer. It is proved that the density of the AlSiMg alloy depends on the scanning strategy used. The calculated density of the specimen was 2.5 g/cm³, which corresponds to the density of silumin. Analysis of SEM images and maps of the distribution of elements (Al, Mg, Si) of the specimens showed that different specimen formation strategies do not affect the nature of silicon distribution. A unique grain structure is observed in the resulting AlSi8Mg alloy. The melt pool consists of small grains along the border and large grains in the center. The formation of fine grains is explained by the addition of Si and the high cooling rate during selective laser melting.

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-laser-melted 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. A novel crack-free Ti-modified Al-Cu-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 Al-7Si-0.6Mg alloy fabricated by selective laser melting, Scripta Materialia, 2019, vol. 160, pp. 66–69. DOI: 10.1016/j.scriptamat.2018.09.045.

11. Zhang H., Gu D., Dai D. Laser printing path and its influence on molten pool configuration, microstructure and mechanical properties of laser powder bed fusion processed rare earth element modified Al-Mg alloy. Virtual and Physical Prototyping, 2022, vol. 17, pp. 308–328. DOI: 10.1080/17452759.2022.2036530.

12. Bhattacharjee R., Datta S., Biswas P. Thermomechanical and material flow analysis during friction stir welding of marine grade aluminum alloy 5083. Journal of Ship Production and Design, 2023, vol. 39 (1), pp. 1–24. DOI: 10.5957/jspd.02220010.

13. Wei P., Wei Z., Chen Z., Du J., He Y., Li J. Fundamentals of radiation heat transfer in AlSi10Mg powder bed during selective laser melting. Rapid Prototyping Journal, 2019, vol. 25 (9), pp. 1506–1515. DOI: 10.1108/rpj-11-2016-0189.

14. Xi L., Wang P., Prashanth K.G., Li H., Prykhodko H.V., Scudino S., Kaban I. Effect of TiB₂ particles on microstructure and crystallographic texture of Al-12Si fabricated by selective laser melting. Journal of Alloys and Compounds, 2019, vol. 786, pp. 551–556. DOI: 10.1016/j.jallcom.2019.01.327.

15. Fan H., Witvrouw A., Wolf-Monheim F., Souschek R., Yang S. Effects of substrate surface treatments on hybrid manufacturing of AlSi7Mg using die casting and selective laser melting. Journal of Materials Science and Technology, 2023, vol. 156, pp. 142–156. DOI: 10.1016/j.jmst.2023.02.009.

16. Maamoun A.H., Xue Y.F., Elbestawi M.A., Veldhuis S.C. The effect of selective laser melting process parameters on the microstructure and mechanical properties of Al6061 and AlSi10Mg alloys. Materials, 2018, vol. 12 (1), p. 12. DOI: 10.3390/ma12010012.

17. Aboulkhair N.T., Simonelli M., Parry L., Ashcroft I., Tuck C., Hague R. 3D printing of aluminium alloys: Additive manufacturing of aluminium alloys using selective laser melting. Progress in Materials Science, 2019, vol. 106, p. 100578. DOI: 10.1016/j.pmatsci.2019.100578.

18. 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.

19. Wu J., Wang X.Q., Wang W., Attallah M.M., Loretto M.H. Microstructure and strength of selectively laser melted AlSi10Mg. Acta Materialia, 2016, vol. 117, pp. 311–320. DOI: 10.1016/j.actamat.2016.07.012.

20. Baitimerov R., Lykov P., Zherebtsov D., Radionova L., Shultc A., Prashanth K. Influence of powder characteristics on processability of AlSi12 alloy fabricated by selective laser melting. Materials, 2018, vol. 11, p. 742. DOI: 10.3390/ma11050742.

21. Saprykina N.А., Chebodaeva V.V., Saprykin A.А., Sharkeev Y.P., Ibragimov E.А., Guseva T.S. Sintez trekhkomponentnogo splava na osnove alyuminiya metodom selektivnogo lazernogo plavleniya [Synthesis of a three-component aluminum-based alloy by selective laser melting]. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2022, vol. 24, no. 4, pp. 151–164. DOI: 10.17212/1994-6309-2022-24.4-151-164.

22. Saprykina N.А., Chebodaeva V.V., Saprykin A.А., Sharkeev Y.P., Ibragimov E.А., Guseva T.S. Optimizatsiya rezhimov selektivnogo lazernogo plavleniya poroshkovoi kompozitsii sistemy AlSiMg [Optimization of selective laser melting modes of powder composition of the AlSiMg system]. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 1, pp. 22–37. DOI: 10.17212/1994-6309-2024-26.1-22-37.