Material characterization of long-term service-exposed GTD-111 nickel based superalloy

Ghorbani, Hassan; Farhangi, Hassan; Malekan, Mehdi

doi:10.1016/j.engfailanal.2023.107061

Cited by 13 publications

(2 citation statements)

References 24 publications

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“…γ' precipitate sizes (Feret's diameter) were obtained from the FESEM images using FIJI software (https://fiji.sc/, Open source, Madison, WI, USA) [35]. Based on the Ostwald-ripening theory [11,12,[36][37][38][39], γ' phase coarsening was used to calculate the in-service temperature in the five samples under study.…”

Section: First-stage Turbine Bladementioning

confidence: 99%

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Computational and Experimental Study on Failure Mechanism of a GTD-111 First-Stage Blade of an Industrial Gas Turbine

Bayro-Lazcano,

Piedra-Gonzalez,

García-Moreno

et al. 2023

Metals

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This paper investigates the root cause of a recurring failure observed in the first-stage blades of an industrial gas turbine. The failure involves the loss of the trailing edge tip of the blades. The study employs a combination of metallographic analysis and computational simulations utilizing the finite element method and computational fluid dynamics. The metallographic analysis reveals significant degradation in the GTD-111 nickel-based superalloy within the region where the failure occurs. This degradation is characterized by the coarsening and coalescence of the gamma prime phase, which can be attributed to localized overheating. Additionally, the computational study enables the calculation of the trajectory, pressure, and temperature profiles of the hot gases, as well as the distribution of temperatures within the blade. These findings demonstrate that the cooling airflow is influenced by the hot gas flow, particularly in the vicinity of the fault location, owing to the orientation of the cooling ducts, which results in overheating in this area. Ultimately, the temperatures derived from the microstructural analysis using the Ostwald-ripening theory align remarkably well with the results obtained from the simulation, validating the accuracy of the computational model. By combining metallographic analysis and computational simulations, this study provides crucial insights into the failure mechanism of the first-stage blades.

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Section: First-stage Turbine Bladementioning

confidence: 99%

“…Another alternative approach to evaluating the in-service temperature is assessing the γ'-phase (Ni 3 Ti) evolution [11][12][13][14][15]. It is well known that nickel-based superalloys undergo microstructural degradation during their lifetime caused by γ'-phase coarsening and coalescence [14].…”

Section: Introductionmentioning

confidence: 99%