INVESTIGATION OF CHARACTERISTICS OF SPECIAL POWDERS AND MATERIALS PRODUCED BY MEANS OF SELECTIVE LASER MELTING

The article presents the results of characterization of special powders of metal alloys and materials produced from these powders by selective laser melting (SLM), including comparative analysis of powders produced using VIGA technology. It is noted the importance of a complex study that includes not only a statistical evaluation of particle size distribution of the powders (preferably, by the method of laser diffraction), but also image analysis providing information on the particles’ shape influencing the powders’ flowability. It is shown that the size distribution and shape metrics for nickel refractory alloys and stainless steel powders obtained at the Powder Metallurgy Institute of the National Academy of Sciences of Belarus are at the level of the best foreign analogues. The influence of powder chemical composition on the mechanical properties of SLM samples is considered. The presence of oxygen and undesirable impurities, as a rule, decreases the strength and tensile strain. It is noted that SLM provides extremely wide opportunities for the formation of complex geometric structures with close to full density. Subsequent thermal or thermal and mechanical processing allows reduction of stresses arising during the SLM, densification of products (if necessary) and regulation of their structure and properties. The prospects of applying the backscattered electron diffraction (EBSD) for analysis of the material structure evolution during SLM and subsequent processing are shown. It is noted that products obtained by the SLM from the powders of special alloys exhibit mechanical properties at a level, and in some cases even exceeding the properties of these alloys produced by traditional and other additive technologies.

special powders, additive technologies, flow rate of powder, selective laser melting

1. Il’yushchenko A. F., Savich V. V. Current state of powder metallurgy in Western Europe: trends and prospects. Poroshkovaya metallurgiya: sbornik statei [Powder metallurgy: collection of scientific papers]. Minsk, 2015, is. 38, pp. 7–18 (in Russian).

2. Il’yushchenko A. F. Effective tool of modern engineering. Nauka i innovatsii = Science and Innovations, 2016, no. 2, pp. 16–21 (in Russian).

3. Il’yushchenko A. F., Savich V. V. Powder metallurgy is one of the first additive technologies. Additivnye tekhnologii, material i konstruktsii: materialy nauchno-tekhnicheskoi konferentsii, Grodno, 5–6 oktyabrya 2016 g. [Additive technologies, materials and constructions: materials of the scientific and technical conference, Grodno, October 6–10, 2016]. Grodno, Grodno State University Publ., 2016, pp. 20–30 (in Russian).

4. Il’yushchenko A. F. Additive technologies and prospects for their development in the State Scientific Institution “Powder Metallurgy Institute”. Sbornik dokladov Mezhdunarodnogo nauchno-prakticheskogo simpoziuma, Minsk, 24 maya 2017 g. [Collection of reports of the International Scientific and Practical Symposium, Minsk, May 24, 2017]. Minsk, Belaruskaya navuka Publ., 2017, pp. 51–65 (in Russian).

5. Dawes J., Bowerman R., Trepleton R. Introduction to the Additive Manufacturing Powder Metallurgy Supply Chain. Johnson Matthey Technology Review, 2015, vol. 59, no. 3, pp.. 243–256. https://doi.org/10.1595/205651315x688686

6. Kippax P., Deffley R. Size and shape optimisation of metal powders for additive manufacturing. Metal Additive Manufacturing, 2015, vol. 1, no. 3, pp. 75–78.

7. Hoeges S., Zwiren A., Schade C. Additive manufacturing using water atomised steel powders. Metal Power Report, 2017, vol. 72, iss. 2, pp. 111–117. https://doi.org/10.1016/j.mprp.2017.01.004

8. Vrancken B. Thijs L., Kruth J.-P., Humbeeck J. V. Heat treatment of Ti6Al4V produced by Selective Laser Melting: Microstructure and mechanical properties. Journal of Alloys and Compounds, 2012, vol. 541, pp. 177–185. https://doi.org/10.1016/j.jallcom.2012.07.022

9. Tillmann W., Schaak C., Nellesen J., Schaper M., Aydinöz M.E., Hoyer K.-P. Hot isostatic pressing of IN718 components manufactured by selective laser melting. Additive Manufacturing, 2017, vol. 13, pp. 93–102. https://doi.org/10.1016/j.addma.2016.11.006

10. Hegab H. A. Design for additive manufacturing of composite materials and potential alloys. Manufacturing Review, 2016, vol. 3, pp. 1–17. https://doi.org/10.1051/mfreview/2016010

11. Singh S. Ramakrishna S., Singh R. Material issues in additive manufacturing: A review. Journal of Manufacturing Processes, 2017, vol. 25, pp. 185–200. https://doi.org/10.1016/j.jmapro.2016.11.006

12. Heynick, M. Additive manufacturing of metals: a review. Materials Science and Technology (MS&T) 2011 October 16–20, 2011, Columbus, Ohio. Available at: https://www.asminternational.org/documents/10192/23826899/cp2011mstp1413.pdf/04f142d0-f1ca-44d4-8a10-891992e5529a (Accessed 19 October 2017).

13. Gu D. D., Meiners W., Wissenbach K., Poprawe R. Laser additive manufacturing of metallic components: materials, processes and mechanisms. International Materials Reviews, 2012, vol. 57, no. 3, pp. 137–164. https://doi.org/10.1179/1743280411y.0000000014

14. Frazier W. E. Metal Additive Manufacturing: A Review. Journal of Materials Engineering and Performance, 2014, vol. 23, no. 6, pp. 1917–1928. https://doi.org/10.1007/s11665-014-0958-z