Structure–phase characteristics and the mechanical properties of single-crystal nickel-based rhenium-containing superalloys with carbide–intermetallic hardening

Resumo

Single crystals of rhenium-containing ZhS32-VI, ZhS32U nickel superalloys with the 〈001〉, 〈011〉, and 〈111〉 crystallographic orientations have been produced by directional solidification. The alloying element segregations and the thermal stability of the microstructure consisting of a γ solid solution and hardened by precipitates of the γ′ phase and MC carbides are studied. The crystal lattice parameters of the γ′ and γ phases; the γ/γ′ misfit; and the liquidus, solidus, and γ′-solvus temperatures of the alloys have been found. The temperature dependence of the γ′-phase solubility has beeisn determined. The temperature–orientation dependences of the tensile strength characteristics in the range 20–1150°C and the low-cycle fatigue at 850°C of the alloy single crystals with the 〈001〉, 〈011〉, and 〈111〉 orientations are presented.