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γ'Ni3Al-based casting alloys have a lower density, higher melting point and resistance to oxidation, and a higher ceiling of operating temperatures than modern heat-resistant nickel alloys. The article discusses the features of the electronic structure and crystallization of domestic (such as VKNA/VIN) and the most advanced foreign (γ' + γ) low-alloyed γ'Ni3Al-based alloys (IC type), and experimental data on the nature of the structures formed during directional crystallization of alloys with different types of alloying and on the nature of the distribution of components in the γ'Ni3Al and γNi phases and structural components in the cellular-dendritic structure of single crystals with 〈111〉 and 〈001〉 crystallographic orientation are presented. The influence of heat treatment on the microstructure, distribution of alloying elements, and mechanical properties of the VKNA type alloys is investigated in a wide range of temperature–time parameters. A comparative analysis of the effect of temperature and duration of heat treatment and cooling rate after heat treatment on the heat resistance of alloys showed that, unlike other Ni3Al-based alloys, for single crystals from the VKNA type economically alloyed alloys and parts made from them (uncooled working blades of aviation gas turbine engines, nozzle apparatuses, jet nozzle spacers, and other parts of the hot path of gas turbine engines), a short-term heat treatment (1150°C/1 h) is necessary and sufficient to relieve casting stresses. The alloys demonstrate high heat resistance at 1100–1200°C and the ability to withstand short-term casting temperatures up to 1250–1300°C. [ABSTRACT FROM AUTHOR]

We performed high-temperature treatment of the Ni–C, Al–C, and Ni–Al–C powder mixtures (5 wt % C (soot)) up to the melting point of the respective metals and found that the melt particles coagulate with formation of Ni, Al, and NiAl (intermetallic) spherical particles, respectively. The Ni particles have almost perfect spherical shape and a multilayer graphite coating. The NiAl particles have a thin graphene (graphite) coating. [ABSTRACT FROM AUTHOR]

A method for synthesis of an intermetallic nickel matrix reinforced with particles of different refractory compounds added at different concentrations is considered. Prepared materials are based on two variants of a Ni3Al–Cr–W–Mo–Ti–Hf alloy: type VKNA-1V alloy and type VKNA-1V alloy with increased tungsten content (VKNA-1V(W)). The intermetallic matrix is reinforced with nanoparticles of the oxides Al2O3, Al2O3 ⋅ Y2O3, and Al2O3 ⋅ Y2O3 ⋅ HfO2, with the content of reinforcing component at 2 and 5 vol %. Samples are compacted by spark plasma sintering. The microstructure of prepared cermet materials (CMs) is investigated using scanning electron microscopy. The impact viscosity and flexural strength are determined. We establish the effect that the content and composition of the reinforcing component has on the physicomechanical properties of the high-temperature CMs based on an intermetallic matrix dispersion-hardened with refractory metal particles. Our findings show that the optimal combination of flexural strength and impact viscosity at room temperature is achieved in the CM sample in which the intermetallic matrix is based on VKNA-1V(W) alloy and the reinforcing component is represented by ternary oxide Al2O3 ⋅ Y2O3 ⋅ HfO2 added at a concentration of 2%. [ABSTRACT FROM AUTHOR]

Abstract—The combined influence of rare earth metals (praseodymium, neodymium, and erbium), the technology of smelting an intermetallic alloy based on nickel aluminide on pure charge materials using 25, 50, and 75 wt % of waste, and the technology of casting single-crystal billets and their heat treatment, combined with hot isostatic pressing, on mechanical properties and long-term strength at the level of certified data are investigated. [ABSTRACT FROM AUTHOR]