Modelling Microstructural Transformations of Nickel Base Superalloy in 718 During Hot Deformation

Guest, Robert P.; Tin, Sammy

doi:10.7449/2005/superalloys_2005_385_397

Cited by 7 publications

(4 citation statements)

References 21 publications

(24 reference statements)

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“…An approach to track the dislocation density as a function of strain has been proposed and utilized to predict the microstructure evolution in Alloy 718. [42] The relationship between the increase in deformation strain dε and the increase in dislocation density dn in this work is given by: dn = (6.6x10 14 )dε (17) Additional efforts have been conducted to model the deformation of Alloy 718 with dislocation density-based constitutive equations. [43] Avrami-type microstructure evolution models have been developed and were shown to be successful in predicting resultant forged microstructures.…”

Section: Review Of Modeling and Simulation Applications To Alloy 718 ...mentioning

confidence: 99%

Modeling and Simulation of Alloy 718 Microstructure and Mechanical Properties

Furrer¹,

Goetz²,

Shen³

2010

Superalloy 718 and Derivatives

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Alloy 718 is a unique superalloy that has been in use for a number of years. It also has the distinction to be utilized throughout the aerospace and general industrial communities. The applications for this material are often very unique and require tailoring of the microstructure and subsequently the mechanical properties to meet these specific needs. To support optimization of Alloy 718 mechanical properties and performance, considerable work has been conducted by the materials community to develop materials and manufacturing process models to aid in the simulation and prediction of the microstructure and mechanical properties of components produced from this alloy. This paper will review various modeling and simulation tools and applications to Alloy 718. This complex alloy is continuing to see optimization efforts through the use of modeling and simulation to support new and enhanced application requirements.

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Section: Review Of Modeling and Simulation Applications To Alloy 718 ...mentioning

confidence: 99%

Modeling and Simulation of Alloy 718 Microstructure and Mechanical Properties

Furrer¹,

Goetz²,

Shen³

2010

Superalloy 718 and Derivatives

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“…Some researchers, as Guest et al [57] worked with grain set models to incorporate the effects of the precipitates using Scheil's additive function. Sellars [29], discusses the effect of secondary phase particles on recrystallization in steel and aluminum alloys.…”

Section: Precipitatesmentioning

confidence: 99%

Microstructural Modeling During Multi-Pass Rolling of a Nickel-Base Superalloy

Subramanian

Cherukuri

2009

Volume 11: Mechanics of Solids, Structures and Fluids

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Superalloys are metallic alloys used for high temperature applications such as encountered in the aircraft industry and where resistance to deformation is a primary requirement. Alloy 718 is one such Nickel-base superalloy that resists deformation at elevated temperatures and is therefore difficult to hot work. One of the major hotworking operations is multi-pass shape rolling in which Alloy 718 undergoes multiple deformations in several passes along with reheating between passes. For a given composition of alloy, the high temperature flow stress is influenced to a large extent by the grain size of the microstructure. In the case of shape rolling in which the cross section changes from circular to oval in alternate passes, the correct working forces, which relate to gauge and shape control as well as to power requirements, can be estimated accurately only if the microstructure relevant to the specific pass of rolling is known. In addition, the microstructure present at the end of the rolling and cooling operations controls the product properties. Control of grain size is an increasingly important characteristic in hotworking. The narrow temperature range (980°C and 1120°C [1]) for hotworking of Alloy 718 makes the grain size control more difficult. During hotworking, Alloy 718 undergoes microscopic and mesoscopic events such as dynamic recrystallization (DRX), metadynamic recrystallization (MDRX) and static grain growth (SGG) depending on the temperature, strain rate and retained strain. Modeling these microstructural events is important in designing the rolling process. Due to the tremendous amount of time, cost and effort associated with experiments and industrial trials, numerical methods are resorted to because of the complexity of the variables involved in multi-pass rolling. One such popular numerical technique, finite element (FE) method can predict process variables such as strain, strain rate and temperature for the deformation process. In general, microstructural modeling relates these process variables to microstructural evolution. During microstructural modeling, constitutive equations describing the microstructural evolutions are developed using experiments, which can then be readily implemented in an FE package capable of modeling rolling processes.

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“…In this context, much research has been directed at understanding the mechanisms and phenomenology of microstructure evolution during hot deformation. Microstructural processes such as dynamic, metadynamic and static recrystallization as well as grain growth in metals [8], and their relation to the hot processing parameters has been studied and modeled in these superalloys, with the bulk of the study mainly concentrated on IN718, an alloy invented almost a half-century ago [9,10,11,12,13,14,15]. Modeling the hot deformation of superalloys during 331 7th International Symposium on Superalloy 718 and Derivatives Edited by:…”

mentioning

confidence: 99%

Modeling the Hot Forging of Nickel-Based Superalloys: IN718 and Alloy 718Plus

Brown¹,

Bammann²,

Elkadiri³

et al. 2010

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

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An internal state variable material model is used to describe the rate-and temperaturedependent large deformation response of the nickel-based superalloys Inconel 718 and Inconel 718 Plus. The current version of the material model describes the elastic-plastic and thermal deformation of metals, having two internal state variables whose evolution equations account for dislocation hardening and static /dynamic recovery processes. Other microstructural features such as recrystallization and grain growth are currenlty being added to the model. Experimental data from mechanical characterization tests of cylindrical and double cone compression specimens are used, respectively, to calibrate the material model and to validate its predictive capability. In general, the calibrated model predicts well the experimental stress/load levels as well as the rate and temperature dependence of the mechanical response of these superalloys.Introduction The superalloys IN718 and IN718Plus have been very well characterized in terms of their chemistry, microstructure (precipitation phases), manufacturing processing and mechanical properties [1,2,3,4] It is well known that the use of the correct chemical components together with an adequate thermo-mechanical processing (deformation processing, heat treatment, aging) develop in these materials the desirable microstructure (precipitate phases) that give these alloys their good elevated temperature strentgh, thermal stability, and hot workability, characteristics needed for the long-term high-temperature environments typical of aircraft engine turbine parts [5]. However, there is still a demand to understand the mechanical behavior at the final stages of the manufacturing process, which is typically a multi-step hot forging process [6].During hot forging processes, the microstructure and mechanical behavior of these superalloys tpically change by metallurgical transformations. Microstructural features such as dislocation structures, annealing phenomena (recovery, recrystallization and grain growth), and precipitate phases are mainly responsible for the final mechanical properties of the material [7], and hence for the performance of the manufactured part during service. In this context, much research has been directed at understanding the mechanisms and phenomenology of microstructure evolution during hot deformation. Microstructural processes such as dynamic, metadynamic and static recrystallization as well as grain growth in metals [8], and their relation to the hot processing parameters has been studied and modeled in these superalloys, with the bulk of the study mainly concentrated on IN718, an alloy invented almost a half-century ago [9,10,11,12,13,14,15]. Modeling the hot deformation of superalloys during 331 7th International Symposium on Superalloy 718 and Derivatives Edited by:

show abstract

Modelling Microstructural Transformations of Nickel Base Superalloy in 718 During Hot Deformation

Cited by 7 publications

References 21 publications

Modeling and Simulation of Alloy 718 Microstructure and Mechanical Properties

Modeling and Simulation of Alloy 718 Microstructure and Mechanical Properties

Microstructural Modeling During Multi-Pass Rolling of a Nickel-Base Superalloy

Modeling the Hot Forging of Nickel-Based Superalloys: IN718 and Alloy 718Plus

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