Modeling microstructural development during the forging of Waspaloy

Shen, G.; Semiatin, S. L.; Shivpuri, Rajiv

doi:10.1007/bf02670767

Cited by 146 publications

(90 citation statements)

References 11 publications

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“…9) For example, Shen et al reported 468 kJ/mol as the activation energy for deformation of Waspaloy and Guimaraes et al estimaed the activation energy for recovery and recrystallization of Waspaloy as 330 and 430 kJ/mol, respectively. 10,11) It's confirmed that the activation energy of deformation obtained in this study is larger than activation energy of diffusion of compositional elements like other materials dominated by dynamic recrystallization behavior. However, the value is relatively small in some degree compared to those in previous reports of Waspaloy.…”

Section: Deformation Behaviorsupporting

confidence: 72%

“…(3) as ¹0.16 and ¹0.0456 for £ A subsolvus and supersolvus temperature region, respectively. 10) This report means that it is difficult to express the relationship between dynamically recrystallized grain diameter and ZenerHollomon parameter in one equation. Moreover the difference in n dyn between both temperature ranges was supposed to be induced by the presence of £ A particles during subsolvus hot working, which would lead Zener pinning of grain boundaries.…”

Section: Dynamically Recrystallized Grain Diametermentioning

confidence: 99%

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Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Matsui¹

2014

Mater. Trans.

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Ni base superalloy is one of the most important key materials for hot section parts in various applications. As for cast and wrought material, it is well known that grain size distribution and recrystallization ratio as well as precipitation condition have considerable effect on mechanical properties. The deformation and dynamic recrystallization behavior of representative Ni base superalloy, Waspaloy were revealed through various kinds of hot compression tests and quantitative relationship available for numerical calculation technology was derived. Dynamically recrystallized grain diameter depended on temperature, strain rate and was independent of the initial grain diameter and strain. The grain diameter could be expressed as a function of the temperature compensated strain rate, i.e., ZenerHollomon parameter quantitatively. Avramitype equation was available for comprehensive and quantitative expression of dynamic recrystallization transition. The approximation was a function of the given strain and strain for the 50% recrystallization which depends on the initial grain diameter and ZenerHollomon parameter.

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Section: Deformation Behaviorsupporting

confidence: 72%

Section: Dynamically Recrystallized Grain Diametermentioning

confidence: 99%

Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Matsui¹

2014

Mater. Trans.

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“…Although there is some scatter in this plot, possibly due to an inhomogeneity of the initial microstructure/texture or inhomogeneous dissolution of primary alpha, the best straight-line fit of the slope yielded an Avrami exponent close to unity. Such a value has been reported a number of times for the recrystallization of hot-worked steels and nickel-base superalloys, [29][30][31] and has been variously ascribed to dimensionality effects, [32,33] in which the recrystallization *Assuming a diffusivity D of~0.1 lm 2 /s [28] and an alpha-particle radius r of 2.5 lm, the dissolution/homogenization time would be of the order of r 2 /2D~30 seconds. front grows in one-dimensional manner, or heterogeneous nucleation involving site-saturation behavior.…”

Section: A Transformation Kineticsmentioning

confidence: 99%

Early Stages of Microstructure and Texture Evolution during Beta Annealing of Ti-6Al-4V

Pilchak

Sargent

Semiatin

2017

Metall Mater Trans A

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The early stages of microstructure evolution during annealing of Ti-6Al-4V in the beta phase field were established. For this purpose, a series of short-time heat treatments was performed using sheet samples that had a noticeable degree of alpha-phase microtexture in the as-received condition. Reconstruction of the beta-grain structure from electron-backscatter-diffraction measurements of the room-temperature alpha-phase texture revealed that microstructure evolution at short times was controlled not by general grain growth, but rather by nucleation-and-growth events analogous to discontinuous recrystallization. The nuclei comprised a small subset of beta grains that were highly misoriented relative to those comprising the principal texture component of the beta matrix. From a quantitative standpoint, the transformation kinetics were characterized by an Avrami exponent of approximately unity, thus suggestive of metadynamic recrystallization. The recrystallization process led to the weakening and eventual elimination of the initial beta texture through the growth of a population of highly misoriented grains.

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“…the coarse grain region and the fine grain region）always occurs; when forging temperature is up to1170ºC (Fig.8b) or above 1150ºC, the uniform grain size distribution is obtained. In other traditional wrought superalloy [7,9], such as IN 718, WASPALOY, etc. the banded structure seldom occurs during their hot working processes.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Primary γ' Distribution on Grain Growth Behavior of GH720Li Alloy

Zhang¹,

Dong²,

Yu³

et al. 2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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In this paper, a series of hot compression tests were carried out under different hot deformation parameters, covering the temperature range of 1000ºC to 1170ºC, strain rate range of 0.01s -1 to 1s -1 and compression reduction of 30%, 50%, and 70%. After that, all specimens were heat treated under the standard heat treatment schedule of GH720Li to investigate its hot deformation characteristics, especially the grain growth behaviors. The further OM and SEM observations were adopted to investigate the interaction mechanism of the primary γ′ distribution and grain growth for GH720Li alloy. The results show that for GH720Li alloy, when hot deformed below γ′ solvus, the banded or bi-model structure always occurs; while hot deformed near or over γ′ solvus, the uniform grain size distribution can be obtained. Further microstructure analysis shows that the bi-model or banded grain size distribution in GH720Li alloy is mainly due to the nonuniform re-dissolving of primary γ′ during heating process; while the uniformity of primary γ′ phase is determined by the uniformity of elements in this alloy. In other word, the homogenizing process for ingot is the key reason for later grain size control.

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Modeling microstructural development during the forging of Waspaloy

Cited by 146 publications

References 11 publications

Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Early Stages of Microstructure and Texture Evolution during Beta Annealing of Ti-6Al-4V

The Effect of Primary γ' Distribution on Grain Growth Behavior of GH720Li Alloy

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Modeling microstructural development during the forging of Waspaloy

Cited by 146 publications

References 11 publications

Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Dynamic Recrystallization Behavior of Waspaloy during Hot Working

Early Stages of Microstructure and Texture Evolution during Beta Annealing of Ti-6Al-4V

The Effect of Primary &gamma;' Distribution on Grain Growth Behavior of GH720Li Alloy

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The Effect of Primary γ' Distribution on Grain Growth Behavior of GH720Li Alloy