Creep notch strengthening and equivalent uniaxial life mapping of notched plate specimens in a nickel-based single-crystal superalloy

For the life assessment of notched components under high-temperature creep conditions, creep rupture tests, microstructural characterization, and numerical simulations were conducted on miniaturized smooth plate tension (MSPT) specimens and miniaturized notched plate tension (MNPT) specimens. The results show that the MNPT specimens exhibited a pronounced notch strengthening effect, with a creep life approximately 1.8 times that of the MSPT specimens. After establishing an equivalent uniaxial life baseline based on the MSPT specimens, circumferentially notched tension (CNT) specimens with the same notch size were introduced to assist in identifying the parameters of the multiaxial stress rupture criteria, and the reference stress factor of the MNPT specimens was subsequently obtained. The prediction results indicate that the creep life of the MNPT specimens falls within a scatter band of ± 1.3. This method enables the conversion of creep data from miniaturized notched plate tension specimens into equivalent uniaxial round-bar life data, providing a feasible approach for assessing the remaining creep life of service components after local sampling.