Peter The Great Saint-Petersburg Polytechnic University, Saint-Petersburg, Russia:

V. S. Sufiiarov, Leading Researcher, e-mail: vadim.spbstu@ya.ru
A. A. Popovich, Professor, Head of Metallurgy, Mechanical Engineering and Transport Institute
E. V. Borisov, Researcher, Post Graduate Student
I. A. Polozov, Engineer, Student

Additive manufacturing is a promising trend for production of metal products. They allow producing parts with complex configurations within a short time. The general principle of additive manufacturing technologies is producing of work pieces from CAD-files by adding material layer by layer. The usage of titanium alloys for manufacturing of parts for aviation industry by additive technologies is a promising direction. One of the most rapidly developing areas of additive manufacturing is the selective laser melting (SLM) of metallic powders. This paper presents the results of the powder Ti – 6 Al – 4 V alloy study, from which bulk samples and work pieces of turbomachine were made by SLM. Results of researching of microstructure and mechanical properties of bulk specimens before and after heat treatment are presented. The initial powder material consists of spherical particles with some satellites. Investigation of phase composition showed that particles are mainly composed of martensite α'-phase. Microstructure of the samples obtained by SLM indicated formation of martensite α'-phase in the form of fine-dispersed acicular precipitates formed because of high cooling rates. This microstructure explains high strength properties of samples before heat treatment (tensile strength 1160 MPa) and their low ductility (3.8%). Heat treatment resulted in partial destruction of martensite phase, thus increasing ductility (to 9.9%) and slightly reducing tensile strength (1090 MPa).

A. V. Grigorev — the Chief Designer of JSC “Klimov” — was also the participant of this work.

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