Авіаційно-космічна техніка та технологія (May 2021)
Development of technology of dispersible retrofitting of heatproof nickeliferous alloys for blades of turbo-engines
Abstract
The paper proposes means of improving the properties of nickel alloys for aircraft gas turbine engines by improving the existing alloys. The efficiency of an aircraft engine depends on the quality of the turbine rotor blades, which are made of heat-resistant alloys. According to the studies, the obtained results of pilot tests of a complex of mechanical properties, high-temperature corrosion of a multicomponent high-temperature nickel alloy ХН59МВТКЮЛ (Ni-Cr-W-Co-Al-Ti-Mo systems). The paper proposes the use of modifiers. An effective means of dispersing the structural components of alloys at the macro and micro levels is the modification of multicomponent alloys with dispersed and nano dispersed compositions. Based on titanium nitride powder, a technological regime for modifying nickel melt with dispersed compositions of plasma chemical synthesis has been developed. The modifier was used in tablet form. Investigated different dosages of the modifier: 0.1…0.03 % by weight. The proposed method allows, with minimal losses at the melting stage, to introduce the required amount of modifier. The temperature and time parameters of the modification are 16500С, the modifier action time is 5…7 minutes. Investigations of the complex mechanical properties and the peculiarities of the formation of the structure of the modified alloy have been carried out. According to the research results, significant refinement of the alloy grain was obtained in comparison with the initial state. The modification led to an increase in mechanical properties: strength by 10 %, impact strength by 35...40 %. Comparison of the nano-modified alloy with the obtained one made it possible to increase the corrosion resistance of the ХН59МВТКЮЛ alloy in an oxidizing environment. At a temperature of 1000 0С, the corrosion depth decreased by 15 %. An increase in resistance to high-temperature corrosion is associated with a more uniform distribution of excess phases in the structure of the modified alloy. The mechanism of action of refractory particles of a modifier in a nickel melt, which are the nuclei of primary crystallization, has been established. The results of the work are of practical value in the manufacture of rotor blades from high-quality heat-resistant nickel alloys with increased parameters of heat resistance and heat resistance.
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