Influence of Refractory Elements on Phase–Structural Stability of Heat-Resistant Corrosion-Resistant Alloys for Gas Turbine Blades

Abstract

One of the ways to improve the performance of gas-turbine engine blades is improvement the alloying complexes of heat-resistant nickel alloys used for casting. The influences of refractory metals on the macro-and microstructure and the properties of alloys of this type are analysed. It is proposed to introduce rhenium and tantalum into a heat-resistant corrosion-resistant nickel alloy for the production of working blades of gas-turbine engines. The paper presents the results of the study of the influence of chemical composition on the phase-structural components of heat-resistant alloy. Phasetransition temperatures for a new heat-resistant corrosion-resistant nickel alloy containing rhenium and tantalum have been established: liquidus temperature is of ≅ 1370°С, solidus temperature is of 1320°С. Studies of the microstructure of the obtained samples in the cast state, after heating and cooling in calorimetric studies, make it possible to confirm that the phasestructural state corresponds to the alloy of this type, it consists of γ-solid solution including γ′-phase and carbides. Rhenium is mainly part of the γ-solid solution, and tantalum strengthens the cell boundaries. When analysing the structures of the studied samples after heating in a calorimeter to 1250°C,