Effect of alloying elements on stacking fault energies of γ and γʹ phases in Ni-based superalloy calculated by first principles

Yang, Wei; Qu, Pengfei; Sun, Jiachen; Yue, Quanzhao; Su, Haijun; Zhang, Jun; Liu, Lin

doi:10.1016/j.vacuum.2020.109682

Cited by 44 publications

(6 citation statements)

References 35 publications

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“…The intrinsic stacking fault energy (ISFE) calculated for fcc nickel in the slip system [112̅](111) was 136 mJ/m 2 , in agreement with previously reported values of 141 mJ/m 2 , 139 mJ/m 2 and 152 mJ/m 2 , and 129 mJ/m 2 . The calculated USFE for this slip system was computed to be 279 mJ/m 2 , also consistent with the reported values of 285 mJ/m 2 , 278 mJ/m 2 , 283 mJ/m 2 , and 280 mJ/m 2 and 301 mJ/m 2 . The GSFE curve for each of the dopants introduced in this study and at varying distances from the stacking fault is shown in Figure .…”

Section: Resultssupporting

confidence: 86%

Impact of Dilute Amounts of Fission Products on the Mechanical Behavior of Ni

Samin

2024

ACS Omega

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Fission products may interact with structural materials in various nuclear energy applications and cause their mechanical performance to deteriorate. Therefore, it is important to study the effects of different fission products on the mechanical properties of structural materials. In this work, nickel was chosen as a model structural material system and dilute amounts of uranium and fission product impurities X = (Tc, Te, Sb, Ce, Eu, and U) up to 4 at % were used. Density functional theory (DFT) calculations were utilized to assess the effects of these substitutional impurities on the elastic behavior of the metal. Additionally, DFT was used to investigate some aspects of plastic response by computing the generalized stacking fault energies on the {111} ⟨112⟩ slip system for all alloying elements and at varying distances away from the stacking fault plane. None of the dopants satisfied the Pugh or Pettifor criteria for embrittlement, and alloying with Tc led to a slight increase in the elasticity of nickel. The phenomenon of Suzuki segregation was observed for all alloying elements, and there was consequently a significant reduction in the intrinsic stacking fault energy. Finally, and based on the analysis of the stacking fault energies, dopants generally led to softening the nickel (except for Tc and Ce), and all of the dopants were correlated with a loss of ductility (except Eu). These findings may be useful to consider in the design of next-generation reactors and nuclear waste management systems.

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Section: Resultssupporting

confidence: 86%

Impact of Dilute Amounts of Fission Products on the Mechanical Behavior of Ni

Samin

2024

ACS Omega

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“…Of course, these changes in the chemical composition of the γ′-phase are also related to the stacking fault energy value (SFE). Yang et al [ 61 ] stated that the elements Cr, Co, Ti, and Mo, with increasing concentration, decreased the matrix γ SFE. In the case of the γ′-phase, the SFE, Co, and Cr with increasing concentration decreased its value and Ti and Mo with increasing concentration increased the SFE value.…”

Section: Resultsmentioning

confidence: 99%

The Hardness Evolution of Cast and the High-Cycle Fatigue Life Change of Wrought Ni-Base Superalloys after Additional Heat Treatment

et al. 2021

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Concerning the use of modern technologies and manufacturing systems in the production of high-stress components from Ni-base superalloys and the optimization of the production process, knowledge of the microstructure–mechanical properties relationship is very important. The microstructure of Ni-base superalloys is very closely related to the chemical composition. With the high number of alloying elements, various phases are presented in the structure of Ni-base superalloys, which have a predominantly positive effect on the mechanical properties, but also phases that reduce, in particular, the heat resistance of these materials. The aim of the presented paper is the quantification of structural parameters of two types of cast alloys, ZhS6K and IN738, where the effect of dwell at 10 and 15 h at 800 °C on the change in morphology and volume fraction of the γ′-phase precipitate was studied. The detected changes were verified by the Vickers hardness test. The IN718 superalloy was chosen as a representative of the wrought superalloy. This alloy was also annealed for 72 h at a temperature of 800 °C, and the quantification of structural parameters was performed by EDS mapping and TEM analysis. Another partial goal was to assess the effect of changes in the volume fraction of the γ′-phase and δ-phase on the change in the high-cycle fatigue life of superalloy IN 718. This superalloy was tested by dynamic cyclic loading with cycle asymmetry parameter R = −1 at an ambient temperature of 22 ± 5 °C and at a temperature of 700 ± 5 °C and with cycle asymmetry parameter R < 1 (three-point bending load) after annealing at 700 °C/72 h. The results of the quantitative analyses and fatigue tests will be further used in optimizing the design of Ni-base superalloy components by modern technologies such as additive technologies for the production of turbine blades and implemented within the philosophy of Industry 4.0.

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“…[ 26 ] Typically, the softening effect of DRV is insufficient to offset work hardening, especially for alloys with low stacking fault energy; thus, stress increased sharply. [ 27 ] The dislocation density increased with strain until the critical strain point, and then, DRX was activated. [ 28 ] Finally, the flow stress was stable at a large strain, indicating that dynamic softening offset work hardening, leading to equilibrium.…”

Section: Resultsmentioning

confidence: 99%

Hot Deformation Behavior of a Powder Metallurgy Superalloy with High γ′ Content

Zhang

Liang³

et al. 2021

Adv Eng Mater

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The hot deformation behavior of a powder metallurgy superalloy EP741NP is studied using isothermal compression testing on a Gleeble‐3500 thermomechanical simulator. Constitutive equations and processing maps are then constructed based on the experimental stress–strain data, and microstructural changes are analyzed by sectioning the compressed samples. The results show that most stress–strain curves are characterized by rapid work hardening and slow flow softening. Steady‐state flow stress is achieved under low strain rates and at high temperatures. Based on experimental stress–strain data, a constitutive equation compensated by strain is constructed, which provides an accurate prediction of flow stress behavior. Due to the dissolution of γ′, the effects of temperature on the processing map are more significant than strain rate and strain. The recrystallization rate at low temperature is limited by the γ + γ′ nucleation mechanism around grain boundaries and prior particle boundaries (PPBs), forming a unique necklace structure. The optimal processing conditions for the EP741NP superalloy are at temperatures of 1150–1170 °C and strain rates of 0.005–0.02 s−1, which produces a significantly refined microstructure free from PPB.

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Effect of alloying elements on stacking fault energies of γ and γʹ phases in Ni-based superalloy calculated by first principles

Cited by 44 publications

References 35 publications

Impact of Dilute Amounts of Fission Products on the Mechanical Behavior of Ni

Impact of Dilute Amounts of Fission Products on the Mechanical Behavior of Ni

The Hardness Evolution of Cast and the High-Cycle Fatigue Life Change of Wrought Ni-Base Superalloys after Additional Heat Treatment

Hot Deformation Behavior of a Powder Metallurgy Superalloy with High γ′ Content

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