Journal articles: 'Ni-based superalloy'

1

Yuan, Kang, Robert Eriksson, Ru Lin Peng, Xin Hai Li, Sten Johansson, and Yan Dong Wang. "Interdiffusion and Microstructure Simulation in Ni and Co Based Overlay Coatings on a Ni Based Superalloy at High Temperatures." Advanced Materials Research 922 (May 2014): 850–55. http://dx.doi.org/10.4028/www.scientific.net/amr.922.850.

Full text

Abstract:

In turbine engines, Ni or Co based alloys are used at high temperature, either as base materials, superalloys, or deposited on the surface of superalloys, as coatings. In the present study, two different MCrAlY overlay coatings, Ni and Co based, on a Ni based superalloy IN792 were aged for different times in air at three temperatures, 900°C, 1000°C and 1100°C. The aging processes were simulated by using DICTRA software by focusing on the interdiffusion behavior in the superalloy-coating systems. The results of simulation captured the main microstructural features observed and were used to analyze the diffusion behavior of alloying elements and the corresponding microstructure development. It was found that coating composition and temperature affected significantly the microstructure near the superalloy-coating interface, and their relations were mapped as a summary.

APA, Harvard, Vancouver, ISO, and other styles

2

Selvaraj, Senthil Kumaran, G. Sundaramali, S. Jithin Dev, R. Srii Swathish, Rahul Karthikeyan, K. E. Vijay Vishaal, and Velmurugan Paramasivam. "Recent Advancements in the Field of Ni-Based Superalloys." Advances in Materials Science and Engineering 2021 (December 27, 2021): 1–60. http://dx.doi.org/10.1155/2021/9723450.

Full text

Abstract:

In this review article, research papers related to recent developments in Ni-superalloy technologies have been reviewed in order to provide an insight into recent achievements and the potential for further study, research, and development in this field. In this paper, studies on various aspects of Ni-based superalloys are reviewed, such as production methods, which include widely used casting methods, as well as unconventional alternative procedures, novel techniques, or simulation and prediction of certain alloy casting properties. Reviewing was done by categorising the papers into 4 major categories: manufacturing of Ni-based superalloys, effects of alloying elements, physical and mechanical properties of Ni-based superalloys, and defects in Ni-based superalloys. The process used to make Ni-superalloy parts can have a huge impact on the production process efficiency, the final product’s quality and properties, and the defects formed in it. Investment casting is one of the most common methods for making Ni-superalloy parts. Manufacturing covers studies on various casting methods used to make Ni-based superalloy components, novel techniques and methods developed to improve casting procedures to produce better products, and alternative manufacturing methods like AM and HIP processing. Similar to production process, the role of alloying elements is also very important. Even minor changes in their compositions can cause significant changes in the final product. Simultaneously, these alloying elements appear to be more efficient in the development of new methods to control product quality, suppress defect formation, and improve material properties such as the creep and fatigue. As a result, the effects of various alloying elements used in castings of Ni-based superalloys are thoroughly examined. A material’s properties are its most important components. They assist the industrialist in selecting or developing a material based on the needs of the application/use. With this in mind, many researchers have conducted extensive research on physical and mechanical properties, as well as how to improve them. Fatigue life, stress rupture, creep properties, impact ductility, strain response, stress relaxation behaviour, and so on are some of the most important physical and mechanical properties of Ni-superalloys. This article thoroughly reviews various studies on these properties, how and by what factors they are affected, and how they can be improved. Another important factor to consider when making Ni-superalloy castings is defect formation, which can affect the properties of the final product. Freckle defects, hot tears, porosities, and slivers are some of the major defects that occur in Ni-superalloys during the casting process. This article also reviews in detail about these defects, how they form, and how they affect the final product. These defects were found to have a significant influence on a variety of properties, such as creep, fatigue behaviour, and fracture mechanism. Topics and areas such as reinforcement of Ni-superalloys with the help of CNCs and 3D printing of Ni-superalloys that can provide scope for potential future research are highlighted based on the above-reviewed papers.

APA, Harvard, Vancouver, ISO, and other styles

3

Monteiro, Waldemar A., and Ingrid A. Dos Santos. "Microstructural evolution of a nickel-based superalloy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 936–37. http://dx.doi.org/10.1017/s0424820100177817.

Full text

Abstract:

Superalloys are indispensable for the superior perfomance and efficien of jet engine turbine disks,turbine blades,combustors,roket shells and many other devices and components used in various industries, in Cluding nuclear, space and aeronautics.Over the last thirty years,nickel-base superalloys has undergone more structural studies than any other superalloy as a result of attempts to correlate its properties to microstructure and heat treatment. To avoid contradictory or inconsistent findings, it is also necessary a carefully microstructural observation of the employed starting materials. In the present paper,we report morphologies relating to the as cast , forged and heat-treated Ni-base superalloy by transmission and scanning electron microscopy. This superalloy contain intermettallic compounds and carbides. The alloy in study was an as cast and also forged Ni-Fe based superalloy with the following chemical composition:

APA, Harvard, Vancouver, ISO, and other styles

4

Taheri, Morteza, Ali Salemi Golezani, and Korosh Shirvani. "Effect of Aluminide Coating on Rapture Behavior of Ni-Based Superalloy GTD-111 in High Temperature." Advanced Materials Research 457-458 (January 2012): 330–33. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.330.

Full text

Abstract:

GTD-111 superalloys are of the newest Ni-based superalloys which because of having good stability and strength in high temperatures are used in manufacturing of hot-gas-path parts of the gas turbines. Because of severe working conditions, application of these superalloys without coating isn't recommended. For this purpose, firstly the superalloy is coated and then is used. In this paper, the effect of Aluminide coating on rapture behavior of the GTD-111 superalloy is investigated. For this purpose, a number of samples made from GTD-111 superalloy have been coated by powder cementation method and have been subjected to rapture test and have been compared to uncoated samples. The results suggest that the presence of coating causes increase of Al content in the surface and contributes in stability of γ´ which is the most important factor of superalloy strength and also causes more life cycle of this superalloy with respect to similar uncoated samples.

APA, Harvard, Vancouver, ISO, and other styles

5

Zhang, Lihui, Erkang Liu, Weijie Xing, Zhaojiang Xue, Wenjie Fan, Yunsong Zhao, Yushi Luo, Changchun Ge, and Min Xia. "The Formation Mechanism of Oxide Inclusions in a High-Aluminum Ni-Based Superalloy during the Vacuum Induction Remelting Process." Metals 14, no. 6 (May 30, 2024): 654. http://dx.doi.org/10.3390/met14060654.

Full text

Abstract:

Oxide inclusions in Ni-based superalloys play a crucial role in determining their mechanical properties, oxidation resistance, and corrosion resistance at high temperatures. In this paper, the source and formation mechanism of different types of oxide inclusions in a high-aluminum Ni-based superalloy were systematically studied. An automatic field emission scanning electron microscope equipped with an energy dispersive spectrometer and a self-designed superalloy inclusion analysis standard was utilized to quantitatively reveal the oxide inclusion characteristics of the high-aluminum Ni-based superalloy prepared via vacuum induction melting (VIM) and vacuum induction remelting (VIR) processes. The experimental results indicate that the typical oxide inclusions in the Ni-based superalloy before the VIR process are irregular MgO·Al2O3 inclusions with sizes of less than 2 μm. After the VIR process, the typical oxide inclusions in the Ni-based superalloy are also MgO·Al2O3 inclusions. However, these oxide inclusions can be classified into three categories: (i) endogenous irregular MgO·Al2O3 inclusions, less than 4.3 μm in size, inherited from the master alloy; (ii) several hundred-micron film-like MgO·Al2O3 inclusions generated as interface reaction products between the MgO crucible and melts; and (iii) millimeter-scale MgO·Al2O3 inclusions and several tens of microns of MgO inclusions from the exfoliation of the MgO crucible matrix.

APA, Harvard, Vancouver, ISO, and other styles

6

Liu, Guanlan, Shengwei Sun, Yaoyun Hu, and Qinglong Zhao. "The Effect of TiC–TiB2 Dual-Phase Nanoparticles on the Microstructure and Mechanical Properties of Cast Ni–Fe-Based Superalloys." Materials 17, no. 23 (November 25, 2024): 5781. http://dx.doi.org/10.3390/ma17235781.

Full text

Abstract:

TiC–TiB2 dual-phase nanoparticles were added into a Ni–Fe-based cast superalloy and their effects on the microstructure and mechanical properties were compared to those of a Ni–Fe-based superalloy with the addition of TiC nanoparticles. The addition of TiC nanoparticles led to the precipitation of a higher volume fraction of carbides. Compared to the addition of TiC, the addition of TiC–TiB2 nanoparticles not only led to the precipitation of carbides but also promoted the formation of flaky borides and a reduction in the precipitation of the Laves phase. The strengthening effect of TiC–TiB2 nanoparticles on the mechanical properties of Ni–Fe-based superalloys was stronger than that of TiC nanoparticles due to more secondary γ’ precipitates. This study provides valuable insights for selecting ceramic nanoparticles to increase the mechanical properties of cast Ni–Fe-based superalloys.

APA, Harvard, Vancouver, ISO, and other styles

7

Liu, Haiding, Dongzhe Wang, Linping Zhou, Jia She, and Wei Wu. "Significant Improvement of Strength in Wrought 945A Ni-Based Superalloy by Aging Treatment." Crystals 11, no. 6 (May 31, 2021): 627. http://dx.doi.org/10.3390/cryst11060627.

Full text

Abstract:

Ni-based superalloys have attracted much attention due to their good resistance to high-temperature and -pressure environments. Compared with the traditional 718 Ni-based superalloy, 945A Ni-based superalloy with a lower Ni content showed better performance in terms of precipitated hardening and corrosion resistance. In this study, the aging behavior and the evolution of mechanical properties of the wrought 945A Ni-based superalloy were investigated. Microstructures were analyzed by scanning electron microscopy (SEM), bright field transmission electron microscopy (TEM), high-resolution TEM and high-angle annular dark field scanning TEM. Mechanical properties were measured by tensile and compressive tests. The results illustrated that the compressive yield stress was significantly improved by increasing aging time from 229 to 809 MPa. The increase was greater than 220%. This improvement was mainly attributed to the precipitates of the γ′ phase and carbides during the aging treatment. The residual dislocations generated by the plastic processes stimulated the formation of these precipitates. The precipitation behavior and the strengthening mechanism are discussed in detail.

APA, Harvard, Vancouver, ISO, and other styles

8

Thomson, R. C., K. F. Russell, and M. K. Miller. "Atom Probe Field Ion Microscopy of Model Ni-Al-Be Superalloys." Microscopy and Microanalysis 3, S2 (August 1997): 695–96. http://dx.doi.org/10.1017/s1431927600010369.

Full text

Abstract:

Nickel-based superalloys used in jet engines consist of a face-centred cubic Ni matrix, γ, containing a high density of Ll2-ordered Ni3Al precipitates, γ´. At high temperatures the strength of the alloy depends primarily on the strength of the γ´ phase, which begins to decrease above approximately 750°C, limiting the maximum operating temperature of the superalloy. The possibility of strengthening the γ´ phase by solid-state precipitation within the γ´ phase has been investigated in model Ni-Al superalloys containing Be. Beryllium, a light element, is also expected to be a potent solid solution strengthener in the γ´ matrix.Four alloys were manufactured with compositions Ni-18.8 at. % Al-1.6% Be, Ni-19.0 at. % Al-2.6% Be, Ni-17.9 at. % Al-5.4% Be and Ni-15.9 at. % Al-11.9% Be. These Al levels result in a volume fraction of γ´ phase similar to that present in a commercial superalloy, and the Be addition places the superalloys in the γ-γ´-NiBe region of the ternary phase diagram, Fig. 1.

APA, Harvard, Vancouver, ISO, and other styles

9

Zenk, Christopher H., Nicklas Volz, Carolin Zenk, Peter J. Felfer, and Steffen Neumeier. "Impact of the Co/Ni-Ratio on Microstructure, Thermophysical Properties and Creep Performance of Multi-Component γ′-Strengthened Superalloys." Crystals 10, no. 11 (November 21, 2020): 1058. http://dx.doi.org/10.3390/cryst10111058.

Full text

Abstract:

The Ni content is a crucial factor for the development of γ′-strengthened Co-based superalloys and some studies have systematically addressed its influence on various properties in model superalloys. In this paper, we report for the first time the influence of the Co/Ni ratio in the more advanced nine-component superalloy ERBOCo-1: exchanging Co and Ni in this Co/Ni-based superalloy while keeping the other alloying elements constants has a big influence on a variety of material properties. The elemental segregation after casting is slightly more pronounced in the alloy with higher Ni-content. Microstructural characterization of this alloy termed ERBOCo-1X after heat-treatment reveals that the precipitates are cuboidal in the Co- and spherical in the Ni-rich alloy, indicating a decrease in the γ/γ′ lattice misfit. Analyzing the elemental partitioning behavior by atom probe tomography suggests that the partitioning behavior of W is responsible for that. Furthermore, it is found that even though Ni exhibits the highest overall concentration, the γ matrix phase is still Co-based, because Ni is strongly enriched in the γ′ precipitates. Creep tests at 900 °C reveal that even though the microstructure looks less favorable, the creep resistance of the Ni-rich alloy is slightly superior to the Co-rich variant.

APA, Harvard, Vancouver, ISO, and other styles

10

Santra, Sangeeta. "Phase Stability, Structure and Thermodynamics of Modified Ni- and Fe-Aluminides." Diffusion Foundations 13 (November 2017): 1–55. http://dx.doi.org/10.4028/www.scientific.net/df.13.1.

Full text

Abstract:

The Ni-aluminides are integral constituents of thermal barrier coatings applied over Ni-based superalloys. These aluminides provide oxidation-resistance by forming a protective α–Al2O3surface layer. The Pt-modified β–NiAl bond coat has been developed with an impetus to increase the service-life of Ni-based superalloys. The Pt-modified β–NiAl bond coat significantly improves the oxidation-resistance of superalloys. An interdiffusion zone containing topologically closed packed phases develops at the bond coat/superalloy interface. This eventually leads to Al-lean γ′–Ni3Al transformation, whose oxidation resistance is inferior to that of β–NiAl. The Pt-group metals Ir and Ru delay this transformation and impart creep-resistance to the bond coat. Recent investigations demonstrate that alloying with transition metals such as Cr, Mo and Fe enhance the mechanical strength. The functional stability of bond coat-superalloy assembly counts on the interfacial reaction and associated local structural variations which is a function of bond coat composition. This chapter elucidates the effect of various alloying elements on phase constitutions, crystallographic structural stability and thermodynamics of Ni-and Fe-aluminides to engineer a prospective bond coat.

APA, Harvard, Vancouver, ISO, and other styles

11

Lin, Sicong, Hao Shen, Guangni Zhou, Weifeng He, and Kai Chen. "A new rejuvenation heat treatment of crept Ni-based superalloy single crystals." IOP Conference Series: Materials Science and Engineering 1249, no. 1 (July 1, 2022): 012017. http://dx.doi.org/10.1088/1757-899x/1249/1/012017.

Full text

Abstract:

Abstract Ni-based superalloys are widely used in harsh environments due to their exceptional high-temperature mechanical properties, and their microstructures are inevitably subjected to degradation, including accumulation of strain/stress, generation of high density of dislocations, and rafting of γ′-particles, under creep damage. To prolong their service life, rejuvenation heat treatment is proposed to restore their microstructure. In this study, a Ni-based superalloy single crystal specimen with 0.15% creep strain is taken as a surrogate of partially served components. The microstructure, including the dislocation density and distribution as well as the size and morphology of γ′-particles, is investigated. Then two comparative heat treatment protocols are applied to the crept superalloy single crystal. Because super-solvus homogenization treatment triggers recrystallization, a recovery pre-annealing step at sub-solvus temperature is designed to relieve the stored deformation energy. After homogenization and aging heat treatment, the single crystalline structure is preserved, and in the meanwhile the γ′-particles are restored to uniform cuboidal morphology and the dislocations are fully eliminated. Our findings provide a route to rejuvenate crept superalloy single crystals.

APA, Harvard, Vancouver, ISO, and other styles

12

Shi, Zhen Xue, Jia Rong Li, Shi Zhong Liu, and Mei Han. "Improvement of Tensile Property of Ni-Based a Single Crystal Superalloy by Ru Addition." Materials Science Forum 788 (April 2014): 477–82. http://dx.doi.org/10.4028/www.scientific.net/msf.788.477.

Full text

Abstract:

Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001] orientation, were prepared in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Ru on the microstructure and tensile property at 25°C, 760°C, 980°C and 1100°C of the single crystal superalloy were investigated. The results show that the size of γ′ particles became uniform, and the cubic shape of the particles turned a little regular after Ru addition. The yield and ultimate tensile strengths of the single crystal superalloy increased with variant degree at different temperatures. The fracture elongation and area deduction decreased at the testing temperatures of 25°C and 760°C, but those increased at 980°C and 1100°C. The tensile fracture mechanism of the single crystal superalloy at different temperature did not change. Finally the relationship between the improvement of tensile strength and Ru addition was discussed.

APA, Harvard, Vancouver, ISO, and other styles

13

Kañetas, Pedro Jacinto Páramo, Jessica Calvo, Pablo Rodriguez-Calvillo, José María Cabrera Marrero, Marco Antonio Zamora Antuñano, and Martha Patricia Guerrero-Mata. "EBSD Study of Delta-Processed Ni-Based Superalloy." Metals 10, no. 11 (November 3, 2020): 1466. http://dx.doi.org/10.3390/met10111466.

Full text

Abstract:

Nickel-based superalloys are extensively used in the aerospace and power generation industries due to their excellent mechanical properties at elevated temperatures and good corrosion resistance. Typically, these alloys require accomplishing critical standards during their manufacturing process. In this study, an Inconel 718 (IN718) Ni-based superalloy was subjected to a delta-processing treatment (DP718) and subsequently deformed at high temperature. Samples were compressed below and above the δ-solvus temperature at two different strain rates of 0.001 s−1 and 0.01 s−1. A detailed microstructural characterization was carried out by the electron backscattered diffraction technique (EBSD). Kikuchi patterns and the orientation relationship of the δ-phase were identified. For samples deformed above the δ-solvus at 0.01 s−1, an increase in the percentage of low angle grain boundaries (LAGB) within deformed grains and a decrease in high angle grain boundaries (HAGB) were observed. Comprehensive observation of the microstructural evolution of IN718 subjected to DP718 using orientation map images was also performed.

APA, Harvard, Vancouver, ISO, and other styles

14

Zhu, Xintao, Qiang Yang, Fu Wang, and Dexin Ma. "Grain Orientation Optimization of Two-Dimensional Grain Selector during Directional Solidification of Ni-Based Superalloys." Materials 13, no. 5 (March 3, 2020): 1121. http://dx.doi.org/10.3390/ma13051121.

Full text

Abstract:

The grain selection method is widely used in industry to produce Ni-based single crystal superalloys. A Z-form two-dimensional (2D) grain selector was designed to obtain high-quality single crystals. To control grain orientation deviation, one of the most important defects of the single crystal superalloys in casting, Z-form 2D grain selectors with different take-off angle were investigated in this study. The MM247LC superalloy single crystal samples were obtained by the Bridgman method modified by the Z-form grain selectors in this study. The Electron Backscattered Diffraction (EBSD) and the Optical Microscopy (OM) were used to observe and measure the grain selection growth and the microstructural evolution and orientation of the single crystal were also discussed. The results show that a Z-form 2D grain selector with an appropriate take-off angle can significantly reduce the deviation of the grain orientation. A single crystal superalloy with a deviation angle less than 6° can be obtained effectively when the take-off angle was 40°.

APA, Harvard, Vancouver, ISO, and other styles

15

Li, Zhong Lin, Qing Yan Xu, Ji Chun Xiong, Jia Rong Li, and Bai Cheng Liu. "Plastic Deformation and Recrystallization of a Ni-Based Single Crystal Superalloy." Materials Science Forum 850 (March 2016): 47–55. http://dx.doi.org/10.4028/www.scientific.net/msf.850.47.

Full text

Abstract:

Plastic deformation and recrystallization of a Ni-based single crystal superalloy were experimentally investigated. Compression and Brinell Indentation were utilized to cause plastic deformation, and thereafter some deformed samples received heat treatment. Surface topography around the indent confirms the anisotropic plasticity of single crystal superalloys. The influential distance below the indent is much larger than that on the indent surface. Microstructural observation by Electron Back-scatter Diffraction (EBSD) shows that it is easier for nucleation and grain boundary migration in the dendritic arms. In addition, the recovery has almost no effect on preventing recrystallization for deformed samples with small plastic strains (around 5%).

APA, Harvard, Vancouver, ISO, and other styles

16

Li, X. Y., J. T. Liu, C. S. Liu, and Y. W. Zhang. "Tensile and creep properties of novel powder metallurgy Ni-based superalloy." Journal of Physics: Conference Series 2680, no. 1 (January 1, 2024): 012016. http://dx.doi.org/10.1088/1742-6596/2680/1/012016.

Full text

Abstract:

Abstract The development of novel powder superalloys for aero-engine turbine disks holds significant implications. In this paper, the microstructure and mechanical properties of a novel powder nickel-based superalloy are evaluated, followed by a brief discussion of the relationship between tensile and creep properties. The results revealed that the new alloy exhibits good microstructural stability after long-term aging and excellent tensile strength at different temperatures. In particular, the creep properties are significantly superior compared to other alloys. In addition, it is verified that the Monkman-Grant relationship modified by tensile parameters has better validity.

APA, Harvard, Vancouver, ISO, and other styles

17

Cho, Jin Hyung, Johan Martinsson, Du Sichen, and Joo Hyun Park. "Desulfurization Behavior of Incoloy® 825 Superalloy by CaO-Al2O3-MgO-TiO2 Slag." Metallurgical and Materials Transactions B 52, no. 6 (October 15, 2021): 3660–70. http://dx.doi.org/10.1007/s11663-021-02338-9.

Full text

Abstract:

AbstractNi-based superalloy, which has excellent high-temperature strength and corrosion resistance, is mainly used in aviation materials, high-performance internal combustion engines, and turbines for thermal and nuclear power generation. For this reason, refining the impurities in Ni-based superalloys is a very important technical task. Nevertheless, the original technology for the melting and refining of Ni-based superalloys is still insufficient. Therefore, in this study, the effect of the CaO-Al2O3-MgO-TiO2 slag on the removal efficiency of an impurity element sulfur in Incoloy® 825 superalloy, one of the representative Ni-based superalloys, was investigated. The desulfurization behavior according to the change of TiO2 content and CaO/Al2O3 (=C/A, basicity) ratio as experimental variables was observed at 1773 K (1500 °C). Although the TiO2 content in the slag increases to 15 mass pct, the mass transfer coefficient of sulfur in molten alloy showed a constant value. Alternatively, under the condition of C/A > 1.0 of slag, the mass transfer coefficient of sulfur showed a constant value, whereas under the condition of C/A < 1.0, the mass transfer coefficient of sulfur greatly decreased as CaO decreased. Hence, in the desulfurization of Incoloy® 825 superalloy using the CaO-Al2O3-MgO-TiO2 slag, the TiO2 content in the slag does not have a considerable effect on the desulfurization rate and desulfurization mechanism (metal phase mass transfer controlled regime), but the basicity of the slag has a significant effect on desulfurization mechanism. When the slag basicity decreases below the critical level, i.e., C/A < 1.0, which is corresponding to sulfur distribution ratio, Ls < 200, it was confirmed that the desulfurization mechanism shifts from the metal phase mass transfer-controlled regime to the slag phase mass transfer-controlled regime due to the variation in the physicochemical properties of the slag such as viscosity and sulfide capacity. In addition, the different desulfurization rates between steel and Ni alloy melts were discussed by employing the diffusivity of sulfur in both systems.

APA, Harvard, Vancouver, ISO, and other styles

18

Szczotok, Agnieszka. "Effect of Two Different Solutionizing Heat Treatments on the Microstructure of the CMSX-4 Ni-Based Superalloy." Solid State Phenomena 246 (February 2016): 15–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.246.15.

Full text

Abstract:

The heat-treatment processes for the precipitation-strengthened nickel-based superalloys are extremely complicated. The solution heat treatments are designed to dissolve the gamma-prime and the secondary carbide phases and allow the optimum re-precipitation of these phases upon cooling or after aging, for various precipitation-strengthened superalloys. The study was conducted to examine the effects of two solutionizing heat treatments on the microstructure of the CMSX4 superalloy. A comparison between the two obtained microstructures was performed.

APA, Harvard, Vancouver, ISO, and other styles

19

Yang, Guo, Hui Zhou, Xueqiao Li, Wenshuai Wang, Haibo Long, Shengcheng Mao, Ze Zhang, and Xiaodong Han. "The Microstructural Degradation of Ni-Based Superalloys with Segregation under the Super-Gravity Condition." Metals 13, no. 2 (February 17, 2023): 416. http://dx.doi.org/10.3390/met13020416.

Full text

Abstract:

The Ni-based superalloy is used as the turbine blade, which is subject to the coupling effect of temperature and super-gravity during service. As the Ni-based superalloys are difficult to become homogenous after using the solid solution heat treatment, a study on morphology and composition distribution of Ni-base superalloys with segregation during microstructural degradation is necessary. This study investigates the microstructure of the ex-service turbine blade and cast samples subjected to the high-temperature centrifugal test. The difference in the size and shape factor of the γ′ phase decreased with the stress caused by the super-gravity condition, indicating a higher magnitude of homogenization degree. The higher stress will also promote the merge of the sub-grain boundaries, leading to a lower density and higher orientational deviation of the sub-grain boundaries.

APA, Harvard, Vancouver, ISO, and other styles

20

Kianicová, Marta, and Jaroslav Trník. "High Temperature Cyclic Oxidation of Coatings on Ni-Based Superalloys." Solid State Phenomena 226 (January 2015): 137–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.226.137.

Full text

Abstract:

The cyclic oxidation behavior of diffusion protective Al and SiAl coatings used on Ni-superalloy namely MAR-M247 at 1100°C for 38 cycles in the air under cyclic heating and cooling conditions has been investigated in the present work. Cyclic oxidation test was carried out in laboratories of Silesian University of Technology in Katowice, Poland. Cylindrical samples were casted from mentioned alloy in factory PBS Velká Bíteš, a.s., Czech Republic. The oxidation kinetics of coated and uncoated superalloys was analyzed by thermo-gravimetric technique. It was observed that all the coated and bare superalloys obey a parabolic rate law of oxidation. SEM/EDX techniques were used to analyses the oxidation products of all samples. MAR-M247 with Al coating showed good oxidation resistance due to the formation of a compact and adhesive thin Al2O3 scale on the surface of the coating during oxidation. SiAl coating showed equally good oxidation resistance. The oxidation progress of uncoated alloy MAR-M247 was very fast.

APA, Harvard, Vancouver, ISO, and other styles

21

Zhu, Qiang, Min Wang, Yuying Sun, Linfu Zhang, Heyong Qin, and Peng Zhang. "Effects of Ultra-Low Temperatures on the Mechanical Properties and Microstructure Evolution of a Ni-Co-Based Superalloy Thin Sheet during Micro-Tensile Deformation." Materials 16, no. 21 (October 24, 2023): 6838. http://dx.doi.org/10.3390/ma16216838.

Full text

Abstract:

With the development of product miniaturization in aerospace, the nuclear industry, and other fields, Ni-Co-based superalloys with excellent overall properties have become key materials for micro components in these fields. In the microforming field, size effects significantly impact the mechanical properties and plastic deformation behavior of materials. In this paper, micro-tensile experiments at room temperature and an ultra-low temperature were carried out to study the effects of initial microstructure and deformation temperature on the deformation behavior of Ni-Co-based superalloy thin sheets. The results show that as the ratio of specimen thickness to grain size (t/d) decreased from 8.6 to 2.4, the tensile strength σb decreased from 1221 MPa to 1090 MPa, the yield strength σs decreased from 793 MPa to 622 MPa, and the elongation decreased from 0.26 to 0.21 at room temperature. When t/d decreased from 8.6 to 2.4, σb decreased from 1458 MPa to 1132 MPa, σs decreased from 917 MPa to 730 MPa, and the elongation decreased from 0.31 to 0.28 at ultra-low temperatures. When t/d decreased from 8.6 to 2.4, the surface roughness of the specimen increased from 0.769 to 0.890 at room temperature and increased from 0.648 to 0.809 at ultra-low temperatures. During the microplastic deformation process of Ni-Co-based superalloy thin sheets, the coupled effects of surface roughening caused by free surface grains and hindered dislocation movement induced by grain boundary resulted in strain localization, which caused fracture failure of Ni-Co-based superalloy thin sheets.

APA, Harvard, Vancouver, ISO, and other styles

22

Matsumaru, Hiroyuki, Shigenari Hayashi, and Toshio Narita. "Interdiffusion between Ni Based Superalloy and Diffusion Barrier Coatings at 1423K." Materials Science Forum 522-523 (August 2006): 285–92. http://dx.doi.org/10.4028/www.scientific.net/msf.522-523.285.

Full text

Abstract:

A diffusion couple study was carried out with Ni-based superalloy / γ’-Ni3Al with or without a Re-based alloy layer. The Re-based alloy containing Re, W, Cr, and Ni was formed on a second generation, single crystal Ni-based superalloy by using electroplating processes to form films of 70at%Re-Ni and Ni-20at%W, followed by Cr-pack cementation at 1573K for 36ks. The superalloy with or without the Re-based alloy layer was bonded to a γ’−Ni3Al alloy in vacuum. Diffusion couples were annealed in an evacuated quartz ampoule at 1423 K for 90 and 360ks. After the 360ks diffusion treatment the Re-based alloy remained sound and suppressed inward Al diffusion from the γ’-Ni3Al, it was further found that outward diffusion of alloying elements from the alloy substrate to the γ’-Ni3Al was also significantly reduced by the Re-based alloy layer.

APA, Harvard, Vancouver, ISO, and other styles

23

Ding, Zhi Ping, Ming Li, Teng Fei Wang, and Rong Hua Yang. "Analysis of Multiaxial Low Cycle Fatigue Life for Single Crystal Ni-Based Superalloy Based on Two-Phase Unit Cell Model." Applied Mechanics and Materials 117-119 (October 2011): 503–8. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.503.

Full text

Abstract:

Based on micro structure of Ni-based single crystal superalloy, a γ/γ’ two-phase unit cell finite element model was established, and its cyclic stress-strain was simulated under tension/torsion cyclic loading. A low cycle fatigue (LCF) life prediction model of single crystal superalloy was proposed by using cyclic plasticity strain energy as a parameter based on energy dissipation theory. Calculation results of macro finite element model and γ/γ’ two-phase unit cell micro finite element model, and multiaxial LCF test data of CMSX-2 Ni-based single crystal superalloy along [001] orientation were applied to fit the LCF life model by multiple linear regression. The results show that the unit cell model not only reflects the microstructure characteristics of single crystal Ni-based superalloy, but also is better than the macro model in accuracy of analysis, and greatly improve the accuracy of fatigue life prediction. Almost test data fall into the factor of 2.0 scatter band.

APA, Harvard, Vancouver, ISO, and other styles

24

Xiao, G. F., Q. X. Xia, Y. Chang, and H. Y. Zhou. "Research on forming limit of Ni-based superalloy during spinning under complex strain path." IOP Conference Series: Materials Science and Engineering 1270, no. 1 (December 1, 2022): 012049. http://dx.doi.org/10.1088/1757-899x/1270/1/012049.

Full text

Abstract:

Ni-based superalloy components with complex shape, such as conical-cylindrical parts, are one of the most important structural components widely used in aviation and aerospace fields. Composite spinning process, consisting of shear spinning and deep drawing spinning, is the most effective method to manufacture this complex component. However, the fracture and wrinkling defects usually occur due to the severe work hardening and complex strain path. Therefore, in order to evaluate the forming limit of Ni-based superalloy during spinning under complex strain path at room temperature, the finite element model of the shear-deep drawing composite spinning was established. The strain path during the shear-deep drawing composite spinning was analysed. The forming limit of Ni-based superalloy was also studied. Then the forming limit diagram of Ni-based superalloy during the shear-deep drawing composite spinning was established. The results show that the limit half cone angle of Ni-based superalloy for shear spinning is 30°; and the limit deep drawing spinning coefficient is 0.63. The strain path can be approximately the superposition of two linear strain paths during shear-deep drawing composite spinning. The safety zone is “wing shaped” in tension-compression strain zone during the shear-deep drawing composite spinning. The experimental results show that the limit diagram can accurately predict the forming defects.

APA, Harvard, Vancouver, ISO, and other styles

25

Stewart, Calvin M., and Ali P. Gordon. "Strain and Damage-Based Analytical Methods to Determine the Kachanov–Rabotnov Tertiary Creep-Damage Constants." International Journal of Damage Mechanics 21, no. 8 (December 21, 2011): 1186–201. http://dx.doi.org/10.1177/1056789511430519.

Full text

Abstract:

In the power generation industry, the goal of increased gas turbine efficiency has led to increased operating temperatures and pressures necessitating nickel-base superalloy components. Under these conditions, the tertiary creep regime can become the dominant form of creep deformation. In response, the classical Kachanov–Rabotnov coupled creep-damage constitutive model is often used to predict the creep deformation and damage of Ni-base superalloys. In this model, the secondary creep behavior can be determined through analytical methods while the tertiary creep behavior is often found using trial and error or numerical optimization. Trial and error may produce no constants. Numerical optimization can be computationally expensive. In this study, a strain-based and damage-based approach to determine the tertiary creep behavior of nickel-base superalloys has been developed. Analytically determined constants are found for a given nickel-base superalloy. Creep deformation and damage evolution curves are compared. Methods to deal with stress dependence are introduced and studied.

APA, Harvard, Vancouver, ISO, and other styles

26

Kaya, Eren, and Birol Akyüz. "Effects of cutting parameters on machinability characteristics of Ni-based superalloys: a review." Open Engineering 7, no. 1 (December 2, 2017): 330–42. http://dx.doi.org/10.1515/eng-2017-0037.

Full text

Abstract:

AbstractNickel based superalloys offer high strength, corrosion resistance, thermal stability and superb thermal fatigue properties. However, they have been one of the most difficult materials to machine due to these properties. Although we are witnessing improved machining strategies with the developing machining, tooling and inspection technologies, machining of nickel based superalloys is still a challenging task due to in-process strains and post process part quality demands.Selecting optimum machining parameters for quality, productivity and profitability is of paramount importance. Many studies have been conducted on various aspects of machinability of nickel based superalloys including defining the optimum cutting parameters, to develop a better understanding of machining them. The recent studies suggest new findings, and discuss previously reported results, related to the concerns of superalloy machining. This review presents the influences of the most significant cutting parameters on various machinability characteristics with respect to the recent studies as well as the previous ones. The reviewed machinability characteristics may be listed as: tool wear, cutting forces and surface integrity.

APA, Harvard, Vancouver, ISO, and other styles

27

Wu, Yidong, Jiemin Gao, Xuanjing Zhang, Jiahui Zheng, and Xidong Hui. "The Effects of Microstructure on the Thermophysical Properties of the K439B Ni-Based Superalloy." Metals 14, no. 9 (September 19, 2024): 1074. http://dx.doi.org/10.3390/met14091074.

Full text

Abstract:

The thermophysical properties of superalloys are critical for the design, fabrication, and service of hot-end components in engines. In this work, the influence of microstructure on the thermophysical parameters including heat conductivity, thermal diffusivity, heat expansion coefficient, and specific heat capacity of the K439B superalloy, which is a prospective cast superalloy for engine casings, were investigated from 100 °C to 900 °C. It has been observed that these properties increase with temperature, especially between 700 °C and 800 °C, for alloys subjected to different heat treatment processes. When compared under the same temperature, these parameters decrease with an increase in the size and volume fraction of the γ′ phase in the alloys. Meanwhile, the interfaces between the γ/γ′ phase and the boundaries between dendrites also impeded the heat treatment. It can be concluded that among the alloys with different heat treatment process, the sequence 1160 °C/4 h + 1080 °C/4 h + 845 °C/20 h exhibited the most stable heat conductivity and lowest heat expansion coefficient, making it advantageous for high-temperature service.

APA, Harvard, Vancouver, ISO, and other styles

28

Liu, Yan-Xing, and Y. C. Lin. "A Yield Stress Model for a Solution-Treated Ni-Based Superalloy during Plastic Deformation." High Temperature Materials and Processes 37, no. 9-10 (October 25, 2018): 849–56. http://dx.doi.org/10.1515/htmp-2017-0096.

Full text

Abstract:

AbstractUp to now, there are few reports on the yield behavior of Ni-based superalloy during plastic deformation. However, an accurate yield stress model is significant for simulating the plastic forming process by cellular automaton or finite element methods. Therefore, the yield behavior of a solution-treated Ni-based superalloy is studied by hot compression tests. In order to evaluate yield stresses from the measured flow stress curves, the yield process is analyzed in terms of dislocation theory. Then, yield stresses at different deformation temperatures and strain rates are clearly determined. The experimental results show that the yield stresses are highly sensitive to deformation temperature and strain rate. The determined yield stress almost linearly increases with the increase of the logarithm of strain rate or the reciprocal of deformation temperature. A yield stress model is developed to correlate the yield behavior of the studied solution-treated Ni-based superalloy with deformation temperature, strain rate, and strengthening effect of alloying elements. The developed model can well describe the yield behavior of the studied solution-treated Ni-based superalloy.

APA, Harvard, Vancouver, ISO, and other styles

29

Kierat, Milena, and Maciej Liśkiewicz. "INFLUENCE OF 2% TITANIUM ADDITION ON MICROSCTRUCTURE AND SELECTED HIGH-TEMPERATURE PROPERTIES OF A NOVEL Co-BASED SUPERALLOY STRENGHTENED WITH L12 PHASE." Journal of Metallic Materials 73, no. 4 (June 7, 2022): 11–14. http://dx.doi.org/10.32730/imz.2657-747.21.4.2.

Full text

Abstract:

This paper contains selected results of primary microsctructure analysis of a novel superalloy, Co-20Ni-10Al-5Mo-2Nb-2Ti. Research on this class of superalloys was started by J. Sato in 2006, and further expanded by S.K. Makineni in 2015. It is implied that Co-based, W-free superalloys will resolve the issues that the aircraft industry currently faces with Ni-based γ/γ’ superalloys. It is believed that the addition of the Ti alloying element will help with γ’ stabilisation due to high Co3(Mo, Al, Nb) fragmentation. Ti content has to be carefully selected to avoid precipitation of harmful phases, such as Co(Ti, Al).

APA, Harvard, Vancouver, ISO, and other styles

30

de Faria Cunha, Filipe Augusto, Rodrigo de Andrade Reis, Samantha Pinto Gonçalves, Frederico Augusto Pires Fernandes, Renato Baldan, and Artur Mariano de Sousa Malafaia. "Cyclic Oxidation Behavior of Conventional and Niobium-Modified MAR-M246 Superalloy at 900 and 1000 °C." Coatings 13, no. 3 (February 25, 2023): 519. http://dx.doi.org/10.3390/coatings13030519.

Full text

Abstract:

Nickel-based superalloys have excellent properties at high temperatures, which makes them appropriate for applications such as turbocharges and aeronautic gas turbines. MAR-M246 is a superalloy developed for these kinds of applications. The objective of this work was to study the total replacement of Ta by Nb in atomic percentage for this superalloy, regarding the oxidation resistance. Although both elements have the same role (form the γ’ precipitates) in nickel-based superalloys, Ta is more expensive than Nb. Thus, this replacement leads to the possibility of a price reduction. This work studied both conventional MAR-M246(Ta) and experimental MAR-M246(Nb) on cyclic oxidation tests at 900 and 1000 °C for up to 180 cycles. The oxide products were characterized by SEM/EDS and XRD analysis. The products of oxidation were mainly TiO2, Al2O3, Cr2O3, NiO, and Ni(Co)Cr2O4. Mass gain variation per unit area was stable for both materials and temperatures. However, spalled areas were detected for tests performed at 1000 °C. The results obtained here suggest that use of Nb instead of Ta can be considered regarding high temperature oxidation for MAR-M246 superalloy.

APA, Harvard, Vancouver, ISO, and other styles

31

Akahoshi, Kuniaki, Kazuhiro Ogawa, and Hideo Miura. "Non-Destructive Evaluation of Creep Damage of Ni-Based Superalloy Using A Scanning Blue Laser Microscope." Key Engineering Materials 353-358 (September 2007): 2391–94. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2391.

Full text

Abstract:

In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-based superalloys under creep and fatigue conditions quantitatively. The refractive index of the gamma-prime phase is found to be smaller than that of the gamma phase in the Ni-based superalloy, when the wavelength of an irradiated laser beam is shorter than 500 nm. Therefore, it is possible to evaluate the creep damage of this material quantitatively and non-destructively by observing the change of the micro texture in a grain (rafting) using a scanning laser microscope.

APA, Harvard, Vancouver, ISO, and other styles

32

Zhang, Hongye, Huihui Wen, Runlai Peng, Ruijun He, Miao Li, Wei Feng, Yao Zhao, and Zhanwei Liu. "Experimental Study at the Phase Interface of a Single-Crystal Ni-Based Superalloy Using TEM." Materials 15, no. 19 (October 5, 2022): 6915. http://dx.doi.org/10.3390/ma15196915.

Full text

Abstract:

The single-crystal Ni-based superalloys, which have excellent mechanical properties at high temperatures, are commonly used for turbine blades in a variety of aero engines and industrial gas turbines. Focusing on the phase interface of a second-generation single-crystal Ni-based superalloy, in-situ TEM observation was conducted at room temperature and high temperatures. Intensity ratio analysis was conducted for the measurement of two-phase interface width. The improved geometric phase analysis method, where the adaptive mask selection method is introduced, was used for the measurement of the strain field near the phase interface. The strained irregular transition region is consistent with the calculated interface width using intensity ratio analysis. An intensity ratio analysis and strain measurement near the interface can corroborate and complement each other, contributing to the interface structure evaluation. Using TEM in-situ heating and Fourier transform, the change of dislocation density in the γ phase near the two-phase interface of the single-crystal Ni-based superalloy was analyzed. The dislocation density decreases first with the increase in temperature, consistent with the characteristics of metal quenching, and increases sharply at 450 °C. The correlation between the variation of dislocation density at high temperatures and the intermediate temperature brittleness was also investigated.

APA, Harvard, Vancouver, ISO, and other styles

33

Ralls, Alessandro M., Mohammadreza Daroonparvar, Merbin John, Soumya Sikdar, and Pradeep L. Menezes. "Solid-State Cold Spray Additive Manufacturing of Ni-Based Superalloys: Processing–Microstructure–Property Relationships." Materials 16, no. 7 (March 30, 2023): 2765. http://dx.doi.org/10.3390/ma16072765.

Full text

Abstract:

Ni-based superalloys have been extensively employed in the aerospace field because of their excellent thermal and mechanical stabilities at high temperatures. With these advantages, many sought to study the influence of fusion-reliant additive manufacturing (AM) techniques for part fabrication/reparation. However, their fabrication presents many problems related to the melting and solidification defects from the feedstock material. Such defects consist of oxidation, inclusions, hot tearing, cracking, and elemental segregation. Consequentially, these defects created a need to discover an AM technique that can mitigate these disadvantages. The cold spray (CS) process is one additive technique that can mitigate these issues. This is largely due to its cost-effectiveness, low temperature, and fast and clean deposition process. However, its effectiveness for Ni-based superalloy fabrication and its structural performance has yet to be determined. This review aimed to fill this knowledge gap in two different ways. First, the advantages of CS technology for Ni-based superalloys compared with thermal-reliant AM techniques are briefly discussed. Second, the processing–structure–property relationships of these deposits are elucidated from microstructural, mechanical, and tribological (from low to high temperatures) perspectives. Considering the porous and brittle defects of CS coatings, a comprehensive review of the post-processing techniques for CS-fabricated Ni superalloys is also introduced. Based on this knowledge, the key structure-property mechanisms of CS Ni superalloys are elucidated with suggestions on how knowledge gaps in the field can be filled in the near future.

APA, Harvard, Vancouver, ISO, and other styles

34

Jiang, Yihan, Haitao Yue, Qiang Li, Guangshuo Ding, and Xinyu Wang. "Study on the Machinability of Ni-Based Superalloy by Milling Parameters and Cooling Methods under Minimal Quantity Lubrication." Applied Sciences 13, no. 5 (February 21, 2023): 2773. http://dx.doi.org/10.3390/app13052773.

Full text

Abstract:

To explore the milling characteristics of Ni-based superalloy under minimal quantity lubrication (MQL), a single-factor experiment was adopted to investigate the milling machinability of GH4169 Ni-based superalloy. The influences of milling parameters and cooling methods on workpiece surface roughness, milling force, and surface hardness were analyzed. The results showed that the milling parameters and cooling methods have significant effects on the milling machinability of GH4169 Ni-based superalloy. The milling force was Fy > Fx > Fz, and the milling force decreased first and then increased with the increasing cutting speed. The surface roughness, surface hardness, and work hardening rate of the workpieces decreased with the increasing cutting speed and increased with the increasing feed per tooth and radial cutting depth. The milling parameters had a nonsignificant effect on the depth of the work hardening layer in GH4169 Ni-based superalloy. The order of cooling methods to obtain the minimum surface roughness and minimum milling force is nanofluid MQL > MQL > air cooling > no cooling.

APA, Harvard, Vancouver, ISO, and other styles

35

Liu, Dengyu, Qingqing Ding, Qian Zhou, Dingxin Zhou, Xiao Wei, Xinbao Zhao, Ze Zhang, and Hongbin Bei. "Microstructure, Mechanical Properties and Thermal Stability of Ni-Based Single Crystal Superalloys with Low Specific Weight." Crystals 13, no. 4 (April 2, 2023): 610. http://dx.doi.org/10.3390/cryst13040610.

Full text

Abstract:

Ni-based single crystal (SX) superalloy with low specific weight is vital for developing aero engines with a high strength-to-weight ratio. Based on an alloy system with 3 wt.% Re but without W, namely Ni-Co-Cr-Mo-Ta-Re-Al-Ti, a specific weight below 8.4 g/cm3 has been achieved. To reveal the relationship among the composition, mechanical properties, and thermal stability of Ni-based SX superalloys, SXs with desirable microstructures are fabricated. Tensile tests revealed that the SX alloys have comparable strength to commercial second-generation SX CMSX-4 (3 wt.% Re and 6 wt.% W) and Rene′ N5 alloys (3 wt.% Re and 5 wt.% W) above 800 °C. Moreover, the elongation to fracture (EF) below 850 °C (>20%) is better than that of those two commercial SX superalloys. During thermal exposure at 1050 °C for up to 500 h, the topological close-packed (TCP) phase does not appear, indicating excellent phase stability. Decreasing Al concentration increases the resistance of γ′ rafting and replacing 1 wt.% Ti with 3 wt.% Ta is beneficial to the stability of the shape and size of γ′ phase during thermal exposure. The current work might provide scientific insights for developing Ni-based SX superalloys with low specific weight.

APA, Harvard, Vancouver, ISO, and other styles

36

Belan, Juraj. "Quantitative Evaluation of Alitize Coating on ŽS6K Ni-Base Superalloy." Materials Science Forum 782 (April 2014): 578–83. http://dx.doi.org/10.4028/www.scientific.net/msf.782.578.

Full text

Abstract:

The aerospace industry is one of the biggest consumers of advanced materials because of its unique combination of mechanical and physical properties and chemical stability. Highly alloyed stainless steel, titanium alloys and nickel based superalloys are mostly used for aerospace applications. The aim of the work is to evaluate protective Al Si coating applied by diffusion annealing on substrate, Ni base superalloy ZS6K. This superalloy is used for turbine blade production in aero jet engine DV 2. Using of protective alitize coating provides an increasing of heat resistance of superalloy surface and increases working temperature up to 800°C. However, overcrossing of working temperature range (for ZS6K turbine blades it is from 705°C to 750°C) sometimes happen and that is the reason for detailed study of protective coating degradation. The alitize coating were evaluated in starting stage and after various time of regular loading in real aero jet engines DV 2. Coating and its degradation was evaluated with help of quantitative metallography methods (metallography software NIS Elements) and colour contrast as well.

APA, Harvard, Vancouver, ISO, and other styles

37

Zhao, Haigen, Wenqi Guo, Wenyue Zhao, Yi Ru, Junwu Wang, Yanling Pei, Shengkai Gong, and Shusuo Li. "Thickness Effects on Oxidation Behavior and Consequent γ’ Degradation of a High-Al Ni-Based Single Crystal Superalloy." Crystals 13, no. 2 (January 29, 2023): 234. http://dx.doi.org/10.3390/cryst13020234.

Full text

Abstract:

High temperature oxidation is considered to play an essential role in the thickness debit effect on the creep rupture life of Ni-based single crystal (SC) superalloys. In order to clarify thickness effects, thin-walled specimens of different thickness (t = 0.1, 0.3, 1.0 mm) were prepared. Cyclic and isothermal oxidation tests of a high-Al Ni-based SC superalloy IC21 were carried out at 900 °C and 1100 °C in order to study the thickness effects on the oxidation behavior and consequent microstructural degradation. Thin-walled specimens of S01-N exhibited a good oxidation resistance when the protective scale-forming elements were enough in the matrix. Specimen thickness tuned the oxidation kinetics by changing the spallation behavior but had few influences on the thermodynamics. The easier stress relief via creep deformation in thin specimens is the main reason behind this phenomenon. Moreover, the obvious temperature effects on the multilayer oxide scales caused the different thickness-related spallation behaviors. Weaker microstructural degradation appeared and was further mitigated by reduced specimen thickness. Sufficient Al content is considered to be indispensable for the formation of protective α-Al2O3 scale with less degradation of matrix during the high temperature oxidation of thin-walled Ni-based SC superalloy castings.

APA, Harvard, Vancouver, ISO, and other styles

38

Zagula-Yavorska, Maryana. "Rhodium influence on the microstructure and oxidation behaviour of aluminide coatings deposited on pure nickel and nickel based superalloy." High Temperature Materials and Processes 38, no. 2019 (February 25, 2019): 621–27. http://dx.doi.org/10.1515/htmp-2019-0008.

Full text

Abstract:

AbstractThe rhodium 0,5 μm thick layer was deposited on pure nickel and CMSX 4 Ni-based superalloy using the electroplating method. The rhodium coated substrates were aluminized by the CVD method. Oxidation resistance of nonmodified and rhodium modified coatings deposited both on nickel and CMSX 4 superalloy was compared. The triple-layer structure of rhodium modified coatings deposited on pure nickel was found. The β-(Ni,Rh)Al, rhodium doped γ'-Ni3Al and rhodium doped γ-Ni(Al) phases were the main components of the coatings on pure nickel. Two layers – additive and interdiffusion ones were identified in coatings deposited on CMSX 4 superalloy. TEM, SEM and XRD analysis revealed that β-(Ni,Rh)Al phase was the main component of the additive layer. Moreover Topologically Closed-Pack σ phases containing refractory elements in the β-(Ni,Rh)Al matrix of the interdiffusion layer were found. The rhodium modified aluminide coatings have better oxidation resistance than the nonmodified ones both on the pure nickel and CMSX 4 superalloy.

APA, Harvard, Vancouver, ISO, and other styles

39

Preis, Jakub, Donghua Xu, Brian K. Paul, Peter A. Eschbach, and Somayeh Pasebani. "Effect of Liquid Miscibility Gap on Defects in Inconel 625–GRCop42 Joints through Analysis of Gradient Composition Microstructure." Journal of Manufacturing and Materials Processing 8, no. 1 (February 14, 2024): 42. http://dx.doi.org/10.3390/jmmp8010042.

Full text

Abstract:

Joining of Cu-based dispersion-strengthened alloys to Ni-based superalloys has garnered increased attention for liquid rocket engine applications due to the high thermal conductivity of Cu-based alloys and high temperature tensile strength of Ni-based superalloys. However, such joints can suffer from cracking when joined via liquid state processes, leading to part failure. In this work, compositions of 15–95 wt.% GRCop42 are alloyed with Inconel 625 and characterized to better understand the root cause of cracking. Results indicate a lack of miscibility between Cu-deprived and Cu-rich liquids in compositions corresponding to 30–95 wt.% GRCop42. Two distinct morphologies are observed and explained by use of CALPHAD; Cu-deprived dendrites with Cu-rich interdendritic zones at 30–50 wt.% GRCop42 and Cu-deprived spheres surrounded by a Cu-rich matrix at 60–95 wt.% GRCop42. Phase analysis reveals brittle intermetallic phases precipitate in the 60–95 wt.% GRCop42 Cu-deprived region. Three cracking mechanisms are proposed herein that provide guidance on the avoidance of defects Ni-based superalloy to Cu-based dispersion strengthened alloy joints.

APA, Harvard, Vancouver, ISO, and other styles

40

Suwardie, John H., Ramon Artiaga, and Jose L. Mier. "Thermal characterization of a Ni-based superalloy." Thermochimica Acta 392-393 (September 2002): 295–98. http://dx.doi.org/10.1016/s0040-6031(02)00112-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Rösler, J., and O. Näth. "Strength of nanoporous Ni-based superalloy membranes." Journal of Physics: Conference Series 240 (July 1, 2010): 012134. http://dx.doi.org/10.1088/1742-6596/240/1/012134.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

ROSLER, J., O. NATH, S. JAGER, F. SCHMITZ, and D. MUKHERJI. "Fabrication of nanoporous Ni-based superalloy membranes." Acta Materialia 53, no. 5 (March 2005): 1397–406. http://dx.doi.org/10.1016/j.actamat.2004.11.038.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Li, Hongyu, Wei Feng, Wuhao Zhuang, and Lin Hua. "Microstructure Analysis and Segmented Constitutive Model for Ni-Cr-Co-Based Superalloy during Hot Deformation." Metals 12, no. 2 (February 18, 2022): 357. http://dx.doi.org/10.3390/met12020357.

Full text

Abstract:

In a thermal simulator of Gleeble-3500, isothermal hot compression tests were performed on a Ni-Cr-Co-based superalloy at deformation temperatures ranging from 1323 K to 1423 K and with strain rates of 0.01, 0.1, 1, and 5 s−1. We obtained the true stress–strain curves, and the microstructures of deformed samples were analyzed by electron backscatter diffraction (EBSD) technique. The segmented constitutive models were developed to predict the flow stress, and the dynamic recrystallization grain size model was established to evaluate the microstructure evolution for a Ni-Cr-Co-based superalloy. It is found that discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) appear simultaneously in the Ni-Cr-Co-based superalloy during hot deformation, with the latter not being active. Comparison between the experimental and predicted results indicates that the proposed models can describe and interpret the work-hardening and dynamic softening behaviors as well as the evolution characteristic of dynamic recrystallization grain size of the Ni-Cr-Co-based superalloy. In the error analysis of the segmented constitutive models, correlation coefficient (R) is 0.988 and average absolute relative error (AARE) is 6.94%, and for the AGS of DRX, R is 0.974 and AARE is 5.83%, which both have good accuracy.

APA, Harvard, Vancouver, ISO, and other styles

44

Qiu, Jun, Tao Yang, Ziyuan Zhang, Qiang Li, Zixin Yan, and Libiao Wang. "On the Anisotropic Milling Machinability of DD407 Single Crystal Nickel-Based Superalloy." Materials 15, no. 8 (April 7, 2022): 2723. http://dx.doi.org/10.3390/ma15082723.

Full text

Abstract:

The DD407 single crystal Ni-based superalloy with a face-centered cubic structure exhibits strong anisotropic characteristics. In order to reveal the material chip formation mechanism and the impact effect of crystal orientations on the materials’ milling machinability, a combination of experimental observations and theoretical analysis were applied in this study. Considering the resolved shear stress and slip system theories, a fundamental theoretical explanation of the milling force and surface quality along different crystal directions on the (001) crystal plane of the DD407 single crystal Ni-based superalloy was proposed based on a previously constructed anisotropic milling model. Our work in this research verifies that [110] crystal direction on the (001) crystal plane of the DD407 single crystal Ni-based superalloy is the most optimal feeding direction during milling, taking into account surface roughness and morphology, slot bottom plastic deformation, work hardening, and chip edge burr feature.

APA, Harvard, Vancouver, ISO, and other styles

45

Rosa, T. S. A., A. F. Ribeiro, Luiz Henrique de Almeida, and Dílson S. dos Santos. "Effects of the Microstructure on the Hydrogen Diffusivity in Ni-Based Superalloy 718." Defect and Diffusion Forum 297-301 (April 2010): 733–38. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.733.

Full text

Abstract:

In some applications involving aggressive environments, common in oil and gas industries, superalloys 718 may suffer hydrogen embrittlement, resulting in degradation of mechanical properties. The aim of this work is to study the interaction of hydrogen with different microstructures in a 1 mm thick plate, annealed and age hardened superalloy 718. In this way, the effects of hydrogen interaction on microstructure were studied via thermal programmed desorption (TPD), tensile tests and scanning electron microscopy (SEM). Samples were studied in as-received, artificially aged and overaged conditions. Hydrogenated samples submitted to tensile tests presented ductility loss when compared to hydrogen free samples, showing the hydrogen embrittlement sensitivity of this alloy. The influence of  phase precipitation on hydrogen diffusivity, as a result of aging treatment, was also discussed in this work.

APA, Harvard, Vancouver, ISO, and other styles

46

Liu, Shuai, Haixin Yu, Yang Wang, Xue Zhang, Jinguo Li, Suiyuan Chen, and Changsheng Liu. "Cracking, Microstructure and Tribological Properties of Laser Formed and Remelted K417G Ni-Based Superalloy." Coatings 9, no. 2 (January 24, 2019): 71. http://dx.doi.org/10.3390/coatings9020071.

Full text

Abstract:

The K417G Ni-based superalloy is widely used in aeroengine turbine blades for its excellent properties. However, the turbine blade root with fir tree geometry experiences early failure frequently, because of the wear problems occurring in the working process. Laser forming repairing (LFR) is a promising technique to repair these damaged blades. Unfortunately, the laser formed Ni-based superalloys with high content of (Al + Ti) have a high cracking sensitivity. In this paper, the crack characterization of the laser forming repaired (LFRed) K417G—the microstructure, microhardness, and tribological properties of the coating before and after laser remelting—is presented. The results show that the microstructure of as-deposited K417G consists of γ phase, γ′ precipitated phase, γ + γ′ eutectic, and carbide. Cracking mechanisms including solidification cracking, liquation cracking, and ductility dip cracking are proposed based on the composition of K417G and processing characteristics to explain the cracking behavior of the K417G superalloy during LFR. After laser remelting, the microstructure of the coating was refined, and the microhardness and tribological properties was improved. Laser remelting can decrease the size of the cracks in the LFRed K417G, but not the number of cracks. Therefore, laser remelting can be applied as an effective method for strengthening coatings and as an auxiliary method for controlling cracking.

APA, Harvard, Vancouver, ISO, and other styles

47

Ding, Qingqing, Hongbin Bei, Xinbao Zhao, Yanfei Gao, and Ze Zhang. "Processing, Microstructures and Mechanical Properties of a Ni-Based Single Crystal Superalloy." Crystals 10, no. 7 (July 3, 2020): 572. http://dx.doi.org/10.3390/cryst10070572.

Full text

Abstract:

A second-generation Ni-based superalloy has been directionally solidified by using a Bridgman method, and the key processing steps have been investigated with a focus on their effects on microstructure evolution and mechanical properties. The as-grown microstructure is of a typical dendrite structure with microscopic elemental segregation during solidification. Based on the microstructural evidence and the measured phase transformation temperatures, a step-wise solution treatment procedure is designed to effectively eliminate the compositional and microstructural inhomogeneities. Consequently, the homogenized microstructure consisting of γ/γ′ phases (size of γ′ cube is ~400 nm) have been successfully produced after a two-step (solid solution and aging) treatment. The mechanical properties of the resulting alloys with desirable microstructures at room and elevated temperatures are measured by tensile tests. The strength of the alloy is comparable to commercial monocrystalline superalloys, such as DD6 and CMSX-4. The fracture modes of the alloy at various temperatures have also been studied and the corresponding deformation mechanisms are discussed.

APA, Harvard, Vancouver, ISO, and other styles

48

Chaturvedi, Mahesh C. "Liquation Cracking in Heat Affected Zone in Ni Superalloy Welds." Materials Science Forum 546-549 (May 2007): 1163–70. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1163.

Full text

Abstract:

Precipitation hardened nickel-based superalloys are widely used in aero and industrial gas turbine engines due to their excellent high temperature strength and remarkable hot corrosion resistance. A drawback of many of these alloys is that they are very difficult to weld due to their high susceptibility to heat affected zone (HAZ) cracking, both during welding and post weld heat treatments (PWHT). Weld cracking in many of these alloys has been attributed mostly to constitutional liquatioin of grain boundary NbC precipitates. however, HAZ cracking has been observed in carbon-free superalloys as well, Therefore, research was initiated to examine grain boundary liquation and cracking in HAZs in a variety of Ni-based superalloys. It was found that intergranular cracking of grain boundaries involved liquation of several other phases, in addition to NbC, that were present in pre-weld microstructure of the alloy. These even included the primary strengthening phase,γ’, in a very widely used superalloy, Inconel 738. In addition, segregation of melting point depressant element B was also observed at gain boundaries in other superalloys, which also caused grain boundaries in HAZ to liquate and resulting in their cracking. An overview of microstructural aspects of different liquation phenomena involved and characteristics of the liquid film contributing to the HAZ microfissuring of nickel superalloys will be discussed in this presentation

APA, Harvard, Vancouver, ISO, and other styles

49

Kodzhaspirov, G. E., A. Borowikow, and M. Terentyev. "Modelling the Hot Deformation Stress-Strain Curve of a Ni-Based Superalloy." Materials Science Forum 762 (July 2013): 753–56. http://dx.doi.org/10.4028/www.scientific.net/msf.762.753.

Full text

Abstract:

A study on the hot deformation behavior and microstructural changes of nickel based superalloy are presented. Constitutive equation allowing the calculation of peak stress was derived. A study of the effect of the temperature-deformation parameters on the kinetic of austenitic heat-resistant superalloy dynamic recrystallization and on the microstructure evolution was performed as well.

APA, Harvard, Vancouver, ISO, and other styles

50

Zhou, Xin, Jie Xiao, Yan Ling Pei, Shu Suo Li, and Sheng Kai Gong. "Effect of Long-Term Aging on the Evolution of γ' and TCP Phases of a Ni₃Al Based Single Crystal Superalloy." Materials Science Forum 849 (March 2016): 482–87. http://dx.doi.org/10.4028/www.scientific.net/msf.849.482.

Full text

Abstract:

The coarsening behavior of γ' phase and precipitation behavior of TCP phase in a Ni3Al based single crystal superalloy were investigated by experimental and calculation. The Re-containing and Mo-rich single crystal superalloy used in this study exhibit good high-temperature strength and oxidation resistance. After fully heat-treated, the experimental superalloys were aged at 1050°C and 1150°C for different time periods from 50h to 1000h. The microstructure after thermal exposure was examined by field emission-scanning electron microscopy (FE-SEM). The results indicated that the coarsening behavior of γ' phase agrees well with the typical Lifshitz-Slyozov-Wagner (LSW) theory. After thermal exposure, both the size and the volume fraction of the TCP phase changed perceptibly.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Ni-based superalloy'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles