Microstructural and mechanical investigations on the heat treatment rejuvenation of a long-term service-exposed GTD-111 Ni-based superalloy

Geranmayeh, Ali; Malekan, Mehdi; Forghani, Farsad; Ghorbani, Hassan

doi:10.1016/j.msea.2022.144381

Cited by 16 publications

(2 citation statements)

References 35 publications

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“…Accordingly, it can be concluded that the increase in the content of Re can strengthen the overall resistance of the model system. The Ni-based single crystal alloy [16][17][18][19] has excellent mechanical properties, which is mainly because of the integration of Re. The hardnesses of the six kinds of Ni-based single crystal alloy samples show certain regularity with the increase in the content of Re.…”

Section: Resultsmentioning

confidence: 99%

Research on the Effect Mechanism of Re on Interface Dislocation Networks of Ni–Based Single Crystal Alloys

Li,

Zhou

2024

Materials

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The effect of interface dislocation networks on the mechanical properties of new Ni–based single crystal alloys containing Rhenium (Re) is very large. Because the interface dislocations are microscopic in the nano–scale range, this has not been investigated, and it is very difficult to prepare new Ni–based single crystal alloys containing Re. Therefore, six kinds of new Ni–based single crystal alloys containing Re were prepared, and the hardness tests and nonlinear ultrasonic lamb wave tests were performed on the samples. It was found that the density of interface dislocation networks increases with the increase in the content of Re, which improves the blocking ability of matrix phase dislocation cutting into precipitated phase and enhances the inhibition of dislocation movement. The nonlinear ultrasonic lamb wave tests showed that the materials exhibit better mechanical properties when the density of the interface dislocation networks increases. Meanwhile, a new molecular dynamics model which is closer to the real state of an Ni–based single crystal alloy was constructed to reveal the evolution mechanism of interface dislocation networks. The results showed that the potential energy of Re atoms at the interface is the lowest, which affects the reduction of the potential energy of other atoms at the interface, and thus the stability of the model is improved. In addition, according to the change in the total length of dislocation loops in the model system, with the increase in the content of Re atoms, the inhibition of dislocation movement by dislocation networks at the interface is strengthened.

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Section: Resultsmentioning

confidence: 99%

Research on the Effect Mechanism of Re on Interface Dislocation Networks of Ni–Based Single Crystal Alloys

Li,

Zhou

2024

Materials

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“…Significantly elevated temperature values were obtained in samples S4 and S5, surpassing the known temperature thresholds for GTD-111 superalloy [53,54]. Consequently, the mechanical behavior of this material is subjected to various concurrent phenomena, including oxidation, which reduces yield strength and fracture toughness.…”

Section: Microstructural Analysismentioning

confidence: 92%

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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Microstructure and selected properties of the solution heat-treated MAR-M247 Ni-based superalloy fabricated via directional solidification

Rakoczy,

Grudzień-Rakoczy,

Cygan

et al. 2023

Int J Adv Manuf Technol

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This work focuses on MAR-M247 Ni-based superalloy manufactured via directional solidification at various withdrawal rates (3.4 or 5.0 mm/min) and shell mold temperatures (1510 °C or 1566 °C) after solution heat-treatment (SHT). Observations and analyses of four casting variants were carried out using thermodynamic simulations, differential scanning calorimetry (DSC), X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), X-ray spectroscopy (EDX), and tensile tests at ambient temperature. The solidus and liquidus temperatures were very similar for all variants and were in the range of 1263–1264 °C and 1356–1359 °C, respectively. The presence of the γ, γ′, MC carbides, and M5B3 phases was confirmed. Microstructure differences were observed depending on the manufacturing parameters. The castings’ dendritic regions consisted of γ′ precipitates surrounded by the matrix, with a mean size ranging from 0.203 to 0.250 μm, depending on the casting parameters. The amount of the MC carbides in the interdendritic spaces was in the range of 1.87–1.92%. The tensile tests determined that castings produced with preheat temperature of 1566 °C were characterized by higher elongation and slightly lower yield strength in comparison to 1510 °C.

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Microstructural and mechanical investigations on the heat treatment rejuvenation of a long-term service-exposed GTD-111 Ni-based superalloy

Cited by 16 publications

References 35 publications

Research on the Effect Mechanism of Re on Interface Dislocation Networks of Ni–Based Single Crystal Alloys

Research on the Effect Mechanism of Re on Interface Dislocation Networks of Ni–Based Single Crystal Alloys

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

Microstructure and selected properties of the solution heat-treated MAR-M247 Ni-based superalloy fabricated via directional solidification

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