The Effect of the Cooling Rates on the Microstructure and High-Temperature Mechanical Properties of a Nickel-Based Single Crystal Superalloy

Wang, Xiaoyan; Meng, Liang; Zhou, Wen

doi:10.3390/ma13194256

Cited by 11 publications

(4 citation statements)

References 27 publications

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“…Thus, the hardness can be improved to a certain extent. In addition, the increased volume fraction of reversed austenite in 3Cu significantly reduced the hardness [ 30 , 31 ], and the combined effect of the two factors reduced the HRC of 3Cu steel compared with that of 1.5Cu steel. At tempering temperatures above 650 °C, the refinement of ε-Cu relative to the grain weakened, along with the reduction in the reversed austenite, balancing each other and making the HRC of the two test steels remain basically the same.…”

Section: Resultsmentioning

confidence: 99%

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel

Jiang

Zhao

2023

Materials

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We investigated the effect of Cu on the formation of reversed austenite in super martensitic stainless steel by using X-ray diffraction (XRD), a transmission electron microscope (TEM) and an energy-dispersive spectrometer (EDS). Our results showed that the microstructure of the steels comprised tempered martensite and diffused reversed austenite after the steels were quenched at 1050 °C and tempered at 550–750 °C. The volume fraction of reversed austenite in the steel with 3 wt.% of Cu (3Cu) was more than that with 1.5 wt.% of Cu (1.5Cu). The transmission electron microscope results revealed that the reversed austenite in 1.5Cu steel mainly had the shape of a thin strip, while that in 3Cu steel had a block shape. The nucleation points and degree of Ni enrichment of reversed austenite in 3Cu steel were higher than those in 1.5Cu steel. The reversed austenite was more likely to grow in ε-Cu enriched regions. Therefore, Cu can promote reversed austenite nucleation and growth. The mechanical properties of 3 Cu steel are obviously better than those of 1.5Cu steel when tempered at 550–650 °C.

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Section: Resultsmentioning

confidence: 99%

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel

Jiang

Zhao

2023

Materials

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“…Feng et al [19] investigated the influence of cooling mode on morphology evolution and γ′ precipitates in NBSC superalloys, observing increased average matrix and precipitation channel widths with decreasing cooling rates. Wang et al [20] scrutinized the impact of varied cooling rates on the microstructure formation of NBSC superalloys. Their results indicated that an escalated cooling rate led to the formation of smaller quantities of the γ′ phase, with air cooling demonstrating optimal uniformity in precipitated γ′ phases and coherence with the γ phase.…”

Section: Introductionmentioning

confidence: 99%

Atomic behavior of nickel-based single crystal superalloy during heat treatment process based on molecular dynamics

Zheng,

Bian,

Chen

et al. 2024

Phys. Scr.

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The heat treatment process plays a pivotal role in enhancing the characteristics of nickel-based single crystal (NBSC) superalloys. Nevertheless, there exists a paucity of comprehensive investigations concerning the microstructural evolution of NBSC superalloys during heat treatment. This study employs a molecular dynamics simulation method to control the temperature of the NBSC superalloy precisely, aiming to unveil intricate details regarding microstructural evolution, temperature distribution patterns, mechanical properties, and other pertinent aspects during the cooling phase. Additionally, a comparative analysis of internal defect evolution under varying cooling rates is undertaken. The findings highlight the consistently heightened activity of atoms in the γ phase compared to those in the γ' phase. Notably, the stability disparity between these phases gradually diminishes as the temperature decreases during the cooling process. At elevated temperatures, the prevalence of amorphous phases and dislocations in the γ phase channel diminishes concomitantly with the temperature reduction. Strain distribution in the alloy primarily concentrates in the γ phase channel and the central cross position of the γ' phase. The temperature reduction correlates with a decline in the alloy model's strain. In the initial phase of strain reduction, stress fluctuation trends in the X, Y, and Z directions exhibit an initial increase followed by a gradual decrease. Furthermore, the atomic number of HCP defects and dislocation density exhibit distinct patterns of change contingent upon the cooling rates employed.

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“…The coarsening of the γ′-phase and the formation of a carbide net at the grain boundaries significantly reduced the tensile strength and reduced the toughness by almost 50%. In their work, Wang et al [ 25 ] described the effect of cooling rate (0.15 °C/s, 0.60 °C/s, 72 °C/s, and 138 °C/s) on the microstructure and high-temperature mechanical properties of the experimental monocrystalline superalloys. They found that as the cooling rate increased, the γ′-phase nucleation rate increased, resulting in an increased volume of this phase.…”

Section: Introductionmentioning

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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The Effect of the Cooling Rates on the Microstructure and High-Temperature Mechanical Properties of a Nickel-Based Single Crystal Superalloy

Cited by 11 publications

References 27 publications

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel

Effect of Cu on the Formation of Reversed Austenite in Super Martensitic Stainless Steel

Atomic behavior of nickel-based single crystal superalloy during heat treatment process based on molecular dynamics

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

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