The evolution history of superalloy powders during hot consolidation and plastic deformation

Tan, Liming; Li, Yunping; Liu, Chenze; Yang, Chunli; Ding, H.B.; Huang, Lan; Liu, Feng; Qin, Zijun; Jiang, Liang

doi:10.1016/j.matchar.2018.03.039

Cited by 26 publications

(10 citation statements)

References 41 publications

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“…As hot compress continue, strain increases gradually, dynamic recrystallization (DRX) occurs. However, when hot compression temperature is low, PPB can hardly be broken, and gradually is stretched into ellipsoid as strain increases [20], leading to the concentration of stress at PPB, microcracks generates and expands along the PPB, leading to the formation of macroscopic cracks eventually. The formation of crack in hot compression are described by the three steps in the schematic, as shown in Figure 6.…”

Section: Macroscopic Cracking Analysismentioning

confidence: 99%

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method

Liu

Tan

et al. 2022

Materials

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Thermo-mechanical process of nickel-based oxide dispersion strengthened (ODS) superalloys is critical to produce desired components. In this study, an efficient method of consolidating powder is introduced to optimize the preparation process, microstructure and properties of nickel-based ODS superalloys. The influences of consolidation temperature, strain rate and ball milling time on the hardness of nickel-based superalloys were studied. The relationship among process, microstructure and hardness was established, the nanoparticles strengthening and grain boundary strengthening in nickel-based ODS superalloys were discussed. The results indicate that long ball milling time, moderately low consolidation temperature and high strain rates are beneficial to improving properties of nickel-based superalloys. Moreover, dispersion strengthening of nanoparticles and grain boundary strengthening play important roles in enhancing nickel-based ODS superalloys.

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Section: Macroscopic Cracking Analysismentioning

confidence: 99%

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method

Liu

Tan

et al. 2022

Materials

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“…A slight dissolution [79] and coarsening [80,81] of these precipitates have been observed in materials submitted to high temperatures. Some numerical works have been developed to account for their presence, for instance, using a particle packing in [82] and an FE framework in [83].…”

Section: Simulation Of Prior Particles Boundary (Ppb) Particlesmentioning

confidence: 99%

Dissolution of the Primary γ′ Precipitates and Grain Growth during Solution Treatment of Three Nickel Base Superalloys

Alvarado

Janeiro

Florez

et al. 2021

Metals

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Second phase particles (SPP) play an essential role in controlling grain size and properties of polycrystalline nickel base superalloys. The understanding of the behavior of these precipitates is of prime importance in predicting microstructure evolutions. The dissolution kinetics of the primary γ′ precipitates during subsolvus solution treatments were investigated for three nickel base superalloys (René 65, AD730 and N19). A temperature-time codependency equation was established to describe the evolution of primary γ′ precipitates of each material using experimental data, the Thermo-Calc software and the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model. The dissolution kinetics of precipitates was also simulated using the level-set (LS) method and the former phenomenological model. The precipitates are represented using an additional LS function and a numerical treatment around grain boundaries in the vicinity of the precipitates is applied to reproduce their pinning pressure correctly. Thus, considering the actual precipitate dissolution, these simulations aim to predict grain size evolution in the transient and stable states. Furthermore, it is illustrated how a population of Prior Particle Boundaries (PPB) particles can be considered in the numerical framework in order to reproduce the grain size evolution in the powder metallurgy N19 superalloy. The proposed full-field strategy is validated and the obtained results are in good agreement with experimental data regarding the precipitates and grain size.

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“…In order to expand the processing window of the as-HIP samples, the as-HIP sample should be followed by hot extrusion not only to obtain fine microstructures but also to disperse the PPB precipitates within grains, as the conventional processing route of P/M superalloys. [16,17]…”

Section: A Effects Of Various Microstructural Factors On Hot Workabimentioning

confidence: 99%

“…In the case of P/M superalloys, there is a concern of the prior particle boundaries (PPBs) which are decorated by brittle precipitates such as oxide and carbide. [10][11][12][13][14][15][16][17][18] It has been found that the PPBs have an adverse effect on the mechanical properties because they tend to act as crack initiation sites and paths. To overcome the PPB-related problem, it is necessary to first clarify how the presence of PPBs in the as-HIP superalloys affects their hot workability, as the effect of PPBs on the hot workability is not yet well understood owing to the difficulty in evaluating it quantitatively through compression tests.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Hot Workability of Powder Metallurgy Ni-Based Superalloy with Different Initial Microstructures

Higashi

Kanno

2020

Metall Mater Trans A

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The effect of the initial microstructure on the hot workability of a powder metallurgy Ni-based superalloy was investigated in the high-temperature range of 950 °C to 1180 °C and strain rate range of 0.001 to 1.0 s−1. Six samples with different initial microstructures were fabricated by various hot isostatic pressing (HIP) conditions and subsequent treatments such as hot extrusion. The coarse-grained samples exhibited low hot workability regardless of the deformation conditions. In contrast, the hot workability of the fine-grained samples significantly varied depending on the deformation conditions. The hot workability exhibited a peak at the sub-solvus temperature of ~ 1100 °C and decreased at temperatures higher and lower than this temperature. In addition, the hot workability decreased monotonically with increasing the strain rate. The prior particle boundaries (PPBs) acted as cavity nucleation sites and crack paths, especially at lower temperatures and higher strain rates, resulting in early fracture and low hot workability. With decreasing the grain size, the hot workability at the peak temperature improved. The extruded sample with the smallest grain size exhibited the best hot workability, owing to the avoidance of PPB fracture and the acceleration of dynamic recrystallization.

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The evolution history of superalloy powders during hot consolidation and plastic deformation

Cited by 26 publications

References 41 publications

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method

Dissolution of the Primary γ′ Precipitates and Grain Growth during Solution Treatment of Three Nickel Base Superalloys

Evaluation of Hot Workability of Powder Metallurgy Ni-Based Superalloy with Different Initial Microstructures

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