A critical-plane-based thermomechanical fatigue lifetime prediction model and its application in nickel-based single-crystal turbine blades

A thickness‐sensitive and orientation‐related creep lifetime prediction method of nickel‐based single crystal superalloy

“…For turbine blades in aero‐engines operating in elevated‐temperature environments, the centrifugal force generated by high‐speed rotation can cause creep damage, which is considered to be one of the principal failure modes of the turbine blades 1 . Nowadays, nickel‐based single crystal superalloys with excellent high‐temperature mechanical properties are widely used for turbine blades 2–5 . Furthermore, in order to improve the cooling efficiency and reduce the weight of turbine blade, the commonly used turbine blade has developed from the traditional solid structure to the hollow thin‐walled structure with complex inner cavity 6–8 .…”

“…1 Nowadays, nickel-based single crystal superalloys with excellent high-temperature mechanical properties are widely used for turbine blades. [2][3][4][5] Furthermore, in order to improve the cooling efficiency and reduce the weight of turbine blade, the commonly used turbine blade has developed from the traditional solid structure to the hollow thin-walled structure with complex inner cavity. [6][7][8] Previous studies have showed that the creep lifetimes of nickel-based single crystal superalloys have obvious thickness debit effect.…”

Damage‐based low‐cycle fatigue lifetime prediction of nickel‐based single‐crystal superalloy considering anisotropy and dwell types

“…12,13,17 For the nickel-based single-crystal superalloys, the slip plane is usually chosen as the critical plane, and then the mechanical parameters on the slip plane (such as Schmid stress and shear strain) are employed to establish the lifetime prediction model. 9,[18][19][20] Although these models can reflect the anisotropy of LCF lifetimes of nickel-based single-crystal superalloys (such as PW1484 and DD6), some of the existing models are questionable to consider the influence of dwell type on LCF lifetime. 12 On the other hand, when the effect of the dwell type on the LCF lifetime is considered, new terms are generally introduced into the lifetime prediction model, which are determined through two methods involving fitting the experimental data or independently charactering damage under different dwell types.…”

“…It was originally employed to estimate the multiaxial lifetime for the polycrystalline material 14–16 and then has been developed to predict the LCF lifetime for the nickel‐based single‐crystal superalloy due to its clear physical meaning 12,13,17 . For the nickel‐based single‐crystal superalloys, the slip plane is usually chosen as the critical plane, and then the mechanical parameters on the slip plane (such as Schmid stress and shear strain) are employed to establish the lifetime prediction model 9,18–20 . Although these models can reflect the anisotropy of LCF lifetimes of nickel‐based single‐crystal superalloys (such as PW1484 and DD6), some of the existing models are questionable to consider the influence of dwell type on LCF lifetime 12 …”

A Novel Method for High Temperature Fatigue Testing of Nickel Superalloy Turbine Blades with Additional NDT Diagnostics

“…The mechanical properties and service life of turbine blades were mostly evaluated using standard specimens [12][13][14][15][16] and numerical stress-strain analysis or model predictions [2,[17][18][19]. However, the results obtained from standard specimen testing are different from these obtained from the full-scale turbine blade testing due to its structural complexity [20].…”