Influence of the Co/Ni Ratio and Dendritic Segregations on the High-Temperature Oxidation Resistance of Multinary Co-Rich Superalloys at 850 °C and 1050 °C

Hagen, S. P.; Weiser, M.; Abu-Khousa, B.; Virtanen, Sannakaisa

doi:10.1007/s11661-022-06620-6

Cited by 4 publications

(2 citation statements)

References 62 publications

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“…The sections of the γ phase and γ ′ phase are shown in Figure 8a,b, respectively, and the blue atoms in Figure 8b are Al atoms. Due to the deviation in lattice constants between the γ phase and the γ ′ phase, there are mismatched dislocations in the interface of the model, and the dislocation density is an important factor affecting the performance of Ni-based single crystal alloys [10][11][12][13][14][15]. The corresponding γ/γ ′ phase interfaces of the six models are shown in Figure 9, and the yellow atoms are Re atoms.…”

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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“…The manufacture of finished products from intermetallic materials is a promising direction in the aerospace and automotive industries for turbine blades, bearings, and exhaust valves [4][5][6]. The replacement of currently existing nickel-based superalloys [7][8][9] with alloys based on titanium aluminides will make it possible to reduce the weight of gas turbine engine parts by up to 1.5-2 times (density of nickel superalloys is about 9 g/cm 3 , whereas that for alloys based on γ-TiAl is about 4 g/cm 3 ). In addition, this will also reduce the cost of their manufacture by up to 30%.…”

Section: Introductionmentioning

confidence: 99%

Relationship between Structure and Properties of Intermetallic Materials Based on γ-TiAl Hardened In Situ with Ti3Al

Авдеева

Bazhina

Antipov

et al. 2023

Metals

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In this work, intermetallic materials based on γ-TiAl in situ strengthened with the Ti3Al phase have been obtained from the initial components of titanium and aluminum under the conditions of free SHS-compression in one technological step and in ten seconds. This method combines the process of the combustion of initial components in the mode of self-propagating high-temperature synthesis (SHS) with high-temperature shear deformation of the synthesized materials. The following initial compositions have been studied (mol): Ti–Al, 1.5 Ti–Al, and 3 Ti–Al. Thermodynamic calculations have been carried out and the actual combustion temperature of the compositions under study has been measured. To increase the exothermicity of the studied compositions, a “chemical furnace” based on a mixture of Ti–C powders has been used, which allows us to increase the combustion temperature and stabilize the combustion front. It has been found that the actual combustion temperature of the selected compositions increased from 890–1120 to 1000–1350 °C. The results of X-ray powder diffraction and SEM are presented, mechanical and tribological characteristics of the obtained materials are measured, and 3D images of wear grooves are given. It has been found that a decrease in Ti molar fraction and an increase in Al molar fraction in the initial mixture lead to an increase in the mechanical (hardness up to 10.2 GPa, modulus of elasticity up to 215 GPa) and tribological characteristics (wear up to 4.5 times, coefficient of friction up to 2.4 times) of intermetallic materials.

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Influence of the W and Ta content on the High-Temperature Oxidation Resistance of Multinary Co/Ni-Based Superalloys at 1050 °C and 1150 °C

Hagen,

Haussmann,

Wahlmann

et al. 2023

High Temperature Corrosion of mater.

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Outstanding inherent environmental resistance is a precondition for the use of superalloys in high-temperature applications. Besides high Al and Cr levels, also refractory metal concentrations (W and Ta) are reported to affect protective scale formation, as these elements are expected to affect the chemical activity and also the transport of protective scale formers within the alloy. In this study, we elucidate the high-temperature oxidation behavior of 3 Co-based (Co/Ni ratio: 1.4) and 3 Ni-based (Co/Ni ratio: 0.7) superalloys differing in W and Ta levels. Time-resolved thermogravimetric analysis (TGA) in synthetic air at 1050 °C and 1150 °C for 100 h, scanning electron microscopy analysis (SEM), thermodynamic calculations using the CALPHAD software Thermo-Calc, and diffusion couple experiments were conducted to assess the impact of the Co/Ni ratio and the refractory metal content on the oxidation performance. The results indicate that a low W content (3 vs. 5 at.%) and a high Ta content (2.1 vs. 1.5 at.%) beneficially affect the oxidation resistance, as alumina scale formation is facilitated.

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Influence of the Co/Ni Ratio and Dendritic Segregations on the High-Temperature Oxidation Resistance of Multinary Co-Rich Superalloys at 850 °C and 1050 °C

Cited by 4 publications

References 62 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

Relationship between Structure and Properties of Intermetallic Materials Based on γ-TiAl Hardened In Situ with Ti3Al

Influence of the W and Ta content on the High-Temperature Oxidation Resistance of Multinary Co/Ni-Based Superalloys at 1050 °C and 1150 °C

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