Peter the Great St. Petersburg Polytechnic University (St. Petersburg, Russia):

D. V. Masaylo, Scientific researcher, e-mail: dmasaylo@gmail.com
A. A. Popovich, Dr. Eng., Prof., Director of the Institute of metallurgy, machine-building and transport
A. V. Orlov, Scientific researcher
E. L. Gyulikhandanov, Dr. Eng., Prof.

The paper presents the results of the structure and mechanical characteristics study of specimens made from a spheroidized heatresistant iron based alloy powder which was obtained from 2 types of additive technologies: selective laser melting and laser cladding. It was established that the structure after production is released tempered martensite with traces of decomposition into a ferritic-carbide mixture. After heat treatment intended for the quenching stresses removal after the additive process in specimens made by selective laser melting technology there is a complete decomposition of martensite into a ferritic-carbide mixture, and in specimens made by laser cladding technology needle-shaped released martensite is observed, there are areas with blurred boundaries which indicates a temper in the heat treatment process. After quenching and tempering martensite forms in specimens made by selective laser melting technology which decomposes after tempering, and in spacimens made by laser cladding the structure is a fine ferritic phase in the form of laminar precipitates that were formed during decay of the needle martensite. The results of the mechanical tests show that after heat treatments, the strength and yield strengths are higher than the values after rolling. At the same time, the value of the relative elongation in these samples is smaller, which is confirmed by fractographic studies.
The work has been performed as part of the implementation of the federal target program «Research and development in priority areas of development of the scientific and technological complex of Russia for 2014–2020» the unique identifier of the project RFMEFI57817X0245.

1. Popovich A. A. et al. Use of additive techniques for preparing individual components of titanium alloy joint endoprostheses. Biomedical Engineering. 2016. Vol. 50, Iss. 3. pp. 202–205.
2. Lyons B. Additive manufacturing in aerospace: Examples and research outlook. Bridge. 2014. Vol. 44. No. 3. pp. 13–19.
3. Popovich A. A. et al. Anisotropy of mechanical properties of products manufactured using selective laser melting of powdered materials. Russian Journal of Non-Ferrous Metals. 2017 Vol. 58, Iss. 4. pp. 389–395.
4. Popovich A., Sufiiarov V., Polozov I., Borisov E., Masaylo D. Additive manufacturing of individual implants from titanium alloy. Proceedings of METAL 2016 – 25^th Anniversary International Conference on Metallurgy and Materials, May 2016. Brno, Czech Republic. Available at: https://www.researchgate.net/publication/313467063_Additive_manufacturing_of_individual_implants_from_titanium_alloy (accessed: 20.03.2019).
5. Conner B. P. et al. Making sense of 3-D printing: Creating a map of additive manufacturing products and services. Additive Manufacturing. 2014. Vol. 1.pp. 64–76.
6. Chua C. K., Leong K. F. 3D Printing and Additive Manufacturing: Principles and Applications (with Companion Media Pack) of Rapid Prototyping. Fourth Edition. World Scientific Publishing Company, 2014. 548 p.
7. Sufiyarov V. Sh., Borisov Е. V., Polozov I. А., Masailo D. V. Control of structure formation in selective laser melting process. Tsvetnye Metally. 2018. No. 7. pp. 68–74.
8. Travyanov А. Ya. et. al. Study of mechanical properties of cellular structures from 03Kh16N15М3 stainless steel depending on parameters of an elementary cell. Chernye Metally. 2018. No. 10. pp. 59–64.
9. Petrovsky P. V. et. al. Dependence of structure and properties of 03Kh16N15М3 on the geometry of cellular structures obtained by the selective laser melting method. Chernye Metally. 2019. No. 3. pp. 49-53.
10. Timothy J. Horn, Ola LA Harrysson. Overview of current additive manufacturing technologies and selected applications. Science progress. 2012. Vol. 95, Iss. 3. pp. 255–282.
11. Ermolaev А. S., Ivanov А. М., Vasilenko S. А. Laser technologies and processes in the manufacture and repair of gas turbine engine parts. Vestnik Permskogo natsionalnogo issledovatelskogo politekhnicheskogo universiteta. Aerokosmicheskaya tekhnika. 2013. No. 35. pp. 49–63.
12. Kablov Е. N. Innovative development of FSUE “VIAM” SSC RF on the implementation of the “Strategic directions of development of materials and technologies for their processing for the period up to 2030”. Aviatsionnye materialy i tekhnologii. 2015. No. 1 (34). pp. 3–33.
13. Frazier W. E. Metal additive manufacturing: a review. Journal of Materials Engineering and Performance. 2014. Vol. 23, No. 6. pp. 1917–1928.
14. Jia Q., Gu D. Selective laser melting additive manufacturing of Inconel 718 superalloy parts: Densification, microstructure and properties. Journal of Alloys and Compounds. 2014. Vol. 585. pp. 713–721.
15. Razumov N. G., Popovich A. A., Wang Q.-S. Thermal Plasma Spheroidization of High-Nitrogen Stainless Steel Powder Alloys Synthesized by Mechanical Alloying. Metals and Materials International. 2018. Vol. 24, Iss. 2. pp. 363–370.
16. GOST 1497-84 Metals. Methods of tension tests. Introduced: 01.01.1986.
17. GOST 5949-75 Sorted and gauged corrosion-resistant, heatresistant and high-temperature steel. Specifications. Introduced: 01.01.1977.
18. Cunningham R. et al. Synchrotron-based X-ray microtomography characterization of the effect of processing variables on porosity formation in laser power-bed additive manufacturing of Ti-6Al-4V. JOM. 2017. Vol. 69, No. 3. pp. 479–484.