Optimization of the composition of the foundry heat-resistant nickel alloy for the manufacture of cast working blades using the method of (mono) crystallization for promising gas turbines

Abstract

Purpose. Development of the composition of a heat-resistant nickel alloy not containing rhenium for the manufacture of cast working blades by the method of directional (mono) crystallization. The alloy should have increased structural stability, while maintaining the level of mechanical, anti-corrosion and heat-resistant properties and a significant reduction in cost.Research methods. To estimate the structural and phase stability of high-temperature nickel alloys, various calculation methods were used: « ΔE-method» for assessing the balance of the chemical composition of the alloys by the value of the unbalance parameter of the doping system; PHACOMP and New PHACOMP – on the chemical composition of γ- solid solutions; developed in ZNTU complex methodology that establishes the relationship between the various parameters of structural stability.Results. Computing-analytical methods have been used to develop the composition of an economically-alloyed heat-resistant nickel alloy for the manufacture of cast blades by the method of directional (mono) crystallization, which does not contain expensive imported rhenium.Scientific novelty. Using computational and analytical methods, a composition of a heat-resistant nickel alloy with increased structural stability, resistance to high-temperature corrosion, and heat-resistant properties necessary for cast single-crystal products has been developed.Improvement of structural stability and improvement of the complex of properties of the developed alloy is provided by balanced doping with tantalum and tungsten (8.5 % at an average level), at reducing the content of carbon, molybdenum and cobalt by almost 2 times, and absence of the most expensive component in the composition – rhenium.Practical value. The developed economically-alloyed heat-resistant nickel alloy, which does not contain expensive rhenium, provides all the necessary operational properties, with a significant reduction in cost, and can be recommended for use in the manufacture of single-crystal cast blades of land-based gas turbine units.