THE EFFECT OF DIRECT LASER GROWTH PATTERNS ON THE STRUCTURE AND PROPERTIES OF TITANIUM ALLOY VT6

The problem of using and developing repair technologies in gas turbine engineering is relevant due to the constantly growing volume of production and the development of gas turbine engines. The manufacturing process of the fan wheel includes stamping followed by machining. The restoration of the fan wheel blades is a promising technology, owing to the high cost of blades in production, as well as the high risk of damage and failure. The most promising repair technology in the aviation engine industry is direct laser growth. The use of low-cost technology for repairing parts by laser clad with the suitable property package compatible with traditional methods of parts production is a priority task. The article presents a comprehensive study of scanning strategies obtained by direct laser growth with coaxial powder feeding on a support plate made of titanium alloy VT6. It is shown that the scanning strategy significantly affects the structure of the pad. The structure affects the mechanical properties. Heat accumulates with an increase in the number of layers. The material warms up and stays at this level for a long time, which can be compared to heat treatment. There is a gradual change in the microstructure from a nonequilibrium one with a different ratio α/α’ to an equilibrium one with a phase composition α + β. All samples are characterized by the formation of elongated columnar grains of the primary β-phase.Multiple thermal cycles lead to the enlargement of the initial β-grain.The data for study in this work is the titanium alloy VT6, which is widely used in the aviation industry.

direct laser growth, titanium alloy VT6, grain size, structure, mechanical properties