Long-term strength and creep resistance of a polycrystalline Re-containing nickel-based superalloy

The work was devoted to the study of long-term strength and creep resistance recently developed heat resistant nickel-based superalloy SDZhS-15 intended for manufacturing discs gas turbine engines. as-cast alloy subjected homogenization treatment, hot forging at subsolvus temperatures with intermediate annealing, solution treatment various aging or only aging. A predominantly fine-grained structure obtained in workpieces after forging. It revealed that T > Ts − 50, where is solvus temperature γ'-phase, led a decrease volume fraction primary γ'-phase an increase γ' precipitates together significant growth γ grains (up d 50 μm). Solution Т = allowed maintaining relatively (dγ =10 – 20 μm) ensured precipitation secondary size about 0.1 μm upon cooling air. Three microstructure conditions were obtained, which tests performed range 650 850°C stresses 400 –1200 MPa. highest values achieved condition To evaluate service life superalloy, methodology based on calculation Larson-Miller parameter used. shown (creep resistance) optimal higher as compared industrial disc superalloys EP741NP Udimet 720. Microstructure examination tested samples did not result changes especially formation topologically close-packed phases. After tests, microcracks observed along grain / interphase boundaries, apparently resulted from development boundary diffusion sliding.