Modelling hot deformation of Inconel 718 using state variables

Zhao, Xiaofan; Guest, Robert P.; Tin, Sammy; Cole, David; Brooks, Jeffery; Peers, M.

doi:10.1179/026708304x4295

Cited by 17 publications

(16 citation statements)

References 3 publications

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“…The dislocation structure developed during plastic deformation constitutes a driving force for microstructural evolution, and dislocations mainly concentrate on subgrain boundaries. A number of work hardening models have been proposed (Sandström and Lagneborg, 1975;Kocks and Mecking, 2003;Zhao et al, 2004;Estrin, 1998), and a simple model developed by Kocks (1976) used to assess the influence of strain hardening and the accumulation of dislocations on the internal stressr is:…”

Section: Modelling Of Dislocation Densitymentioning

confidence: 99%

Modelling mechanical property recovery of a linepipe steel in annealing process

Lin

Dean

et al. 2009

International Journal of Plasticity

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Section: Modelling Of Dislocation Densitymentioning

confidence: 99%

Modelling mechanical property recovery of a linepipe steel in annealing process

Lin

Dean

et al. 2009

International Journal of Plasticity

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“…On the other hand, in order to accurately simulate hot forging process by means of numerical techniques such as finite element method, it is important to precisely understand the constitutive equations which describe the dependence of the flow stress on the strain, strain rate and temperature. In the past two decades, many studies have been carried out to characterize the high temperature flow behaviour in IN718 [22][23][24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Flow characteristics and intrinsic workability of IN718 superalloy

Chen

Liu

et al. 2015

Materials Science and Engineering: A

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a b s t r a c tThis study focuses on deformation characteristics of superalloy IN718 by formulation of a new flow stress model and detailed evaluation of intrinsic workability through the generation of three-dimensional (3D) processing maps with the support of optical microstructural observations. Based on thermomechanical simulation tests using a Gleeble-1500 machine, the flow stress model for superalloy IN718 was built and the flow stress throughout the entire deformation process was described by a peak stress only depending on Zener-Hollomon parameter and strain. The developed model exhibited the strain softening due to dynamic recrystallisation (DRX). The intrinsic workability was further investigated by constructing 3D processing maps. The 3D processing maps described the variations of the efficiency of power dissipation and flow instability domains as a function of strain rate, temperature and strain, from which the favourite deformation conditions for thermomechanical processing of IN718 can be established.

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“…In this case, a state variable model incorporating microstructural parameters was utilized to accurately predict the mechanical flow behavior of the metal during forging. [37] Model equations were formulated in terms of the evolution of an internal back stress ( b ), which is related to the hardening and recovery associated with the formation of dislocation networks, and to the kinetics of dynamic recrystallization. With the dominant deformation mechanisms that are operative during conventional forging operations of Ni-based superalloys being identical to those corresponding to high-temperature creep, this behavior can be described using a modified power-law creep equation.…”

Section: E Forgingmentioning

confidence: 99%

Integrated modeling for the manufacture of Ni-based superalloy discs from solidification to final heat treatment

Tin

Lee

Kermanpur

et al. 2005

Metall Mater Trans A

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Process models of the various stages of gas-turbine disc manufacture have been integrated to simulate the physical and microstructural transformations occurring within a nickel-based superalloy throughout the entire manufacturing route. Production of these critical rotating structural components requires several distinct processing stages: vacuum-induction melting (VIM), vacuum-arc remelting (VAR), homogenization heat treatment, cogging, forging, final heat treatment, and machining. During the course of these consecutive manufacturing stages, the various thermal and thermomechanical processes lead to significant changes in both the microstructural characteristics and internal stresses in the alloy. Although separate models have previously been developed to simulate the individual processing stages, this article describes how these models, which are explicitly expressed in terms of the initial and evolving microstructure, can be integrated to simulate the entire manufacturing process from secondary melting through to the final forging and heat treatment. The grain structure predicted for one stage is explicitly transferred as the initial conditions for the model, which simulates the grain evolution during the next step. This information also provides the basis of microstructure-explicit constitutive equations describing the material behavior. Industrial-scale manufacturing trials associated with the production of an INCONEL alloy 718 aeroengine turbine disc were used to validate the integrated model for grain size. The model also allows intrinsic or extrinsic defects entrained within the material during the initial solidification stage to be tracked through the subsequent processes. This provides a basis for calculating the areas of discs likely to be vulnerable to such defects and whether they might be removed during machining. It was shown that the microstructure of the alloy changes significantly throughout the process chain, the final microstructure and defect distribution at each stage being related to those formed in the previous stages. There was good agreement between the model predictions and experimental observations for both the intermediate and final processing stages. The implications of such integrated modeling for quality assurance through process control are discussed.

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Modelling hot deformation of Inconel 718 using state variables

Cited by 17 publications

References 3 publications

Modelling mechanical property recovery of a linepipe steel in annealing process

Modelling mechanical property recovery of a linepipe steel in annealing process

Flow characteristics and intrinsic workability of IN718 superalloy

Integrated modeling for the manufacture of Ni-based superalloy discs from solidification to final heat treatment

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