Saint-Petersburg State Polytechnical University, Saint-Petersburg, Russia:

V. Sh. Sufiiarov, Leading Researcher, e-mail: vadim.spbstu@yandex.ru

A. A. Popovich, Director of Institute of Metallurgy, Mechanical Engineering and Transport

E. V. Borisov, Post-Graduate Student, Researcher

I. A. Polozov, Engineer

This article carried out the complex investigations of selective laser meltingof heat-resistant nickel alloy Inconel 718. Initial material was researched. In particular, there are given the results of research of morphology, granulometric composition, evolution of structure and phase composition, and nickel alloy powder, obtained by gas atomization technology. Investigation of the powder particles has shown that it has the good flow rate, more than 90% of -Ni phase; and its particles' shape is close to spherical (however, some of them include satellites). There was carried out the study of SLM parameters influence (laser power and speed, scanning strategy) on porosity of samples, produced from Inconel 718 powder. Laser power, laser scanning speed and hatch distance were used as variable parameters. The best result (relative density of 99.7%) was achieved, using the following parameters: laser power of 245 W, laser scanning speed of 755 mm/s and hatch distance of 90 μm. Mechanical tests on samples, produced from Inconel 718 alloy, have shown that their strength and ductility properties are comparable to those of the samples, obtained by casting technology without heat treatment. In particular, tensile strength of 851–949 MPa, yield strength of 569–609 MPa and elongation break of 9.8–31.7% were determined. Further improvement of the quality and properties of samples requires the research of microstructure and phase content evolution before and after heat treatment, aimed at optimizing phase content and structure, as well as removal of thermal and shrinkage stresses.

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