Multimodal size distributions of γ′ precipitates during continuous cooling of UDIMET 720 Li

Radis, Rene; Schaffer, Miroslava; Albu, Mihaela; Kothleitner, Gerald; Pölt, Peter; Kozeschnik, Ernst

doi:10.1016/j.actamat.2009.08.002

Cited by 177 publications

(61 citation statements)

References 33 publications

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“…Such consideration is confirmed by Figure 5 where our results are compared to data available in the literature for either sub-solvus alloys [11], or super-solvus ones [10,12,13,15]. Power law dependence of the average diameter d to the cooling rates…”

Section: Grain Sizesupporting

confidence: 72%

Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Vaunois¹,

Devaux²,

Flageolet³

et al. 2010

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

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The tensile properties of a forged UDIMET 720Li alloy have been investigated at room temperature. The aim of this study was to increase both yield and ultimate tensile stresses using adequate thermal treatments. Classical three steps heat treatments after hot forging were applied: a solution treatment followed by a quench and a two steps aging treatment. Several combinations were investigated: four hours solution treatments, either sub-solvus (1080 C -1120 C) or super-solvus (1160 C); two different cooling rates (10 C/min or 3600 C/min); four different two-steps aging treatments: 650 C/24h/Air Quench (AQ) + 760 C/16h/AQ, 760 C/16h/AQ + 650 C/24h/AQ, 700 C/24h/AQ + 815 C/16h/AQ, 815 C/16h/AQ + 700 C/24h/AQ. The tensile properties appeared to be maximized with the following combination of heat treatments: sub-solvus solutioning (1120 C or 1080 C), fast cooling rate (oil quench, 3600 C/min), and the 760 C/16h/AQ + 650 C/24h/AQ aging. Both EBSD measurements and systematic stereological analyses were performed to characterize for each condition, grain size and γ' distribution (primary γ', secondary γ', tertiary γ'), respectively. The increase of the 0.2% yield stress, is managed by a competition between keeping a small grain size (i.e. by using a low temperature sub-solvus solution treatment) and increasing the intragranular γ' content (i.e. by increasing the solutioning temperature). In order to evaluate the relative contributions to the deformation mechanisms of grain size and of γ' particles, especially intergranular one (primary γ'), Scanning Electron Microscope (SEM) insitu tensile tests have been performed at room temperature on both sub-and super-solvus samples. It is finally demonstrated that the main controlling parameter to reach a very high yield stress is grain size.

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Section: Grain Sizesupporting

confidence: 72%

Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Vaunois¹,

Devaux²,

Flageolet³

et al. 2010

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

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“…The models for the precipitation kinetics, including classic nucleation, diffusion controlled growth, and coarsening, are well developed [12,14,66,67,85] and have been successfully applied to simulate the γ precipitation in Ni-based superalloys [3,5,64,65,68,74]. Olson et al validated a similar precipitation model implemented in PrecipiCalc for 3rd generation disk alloys [64,65].…”

Section: γ Precipitationmentioning

confidence: 99%

A Computational Framework for Material Design

Kattner

Campbell

2017

Integr Mater Manuf Innov

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A computational framework is proposed that enables the integration of experimental and computational data, a variety of user-selected models, and a computer algorithm to direct a design optimization. To demonstrate this framework, a sample design of a ternary Ni-Al-Cr alloy with a high work-to-necking ratio is presented. This design example illustrates how CALPHAD phase-based, composition and temperature-dependent phase equilibria calculations and precipitation models are coupled with models for elastic and plastic deformation to calculate the stress-strain curves. A genetic algorithm then directs the search within a specific set of composition and processing constraints for the ideal composition and processing profile to optimize the mechanical properties. The initial demonstration of the framework provides a potential solution to initiate the material design process in a large space of composition and processing conditions. This framework can also be used in similar material systems or adapted for other material classes.Keywords Ni-based superalloy · Integrated computational materials engineering · Genetic algorithm · Material design

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“…G* contains the cube of the interfacial energy over the square of the driving force ∆G vol . Since G* appears in the exponent of the nucleation rate equation (1), small changes in γ and/or ∆G vol can lead to significant variations in J, which is demonstrated in a treatment of the evolution of multimodal size distributions in the nickel-base superalloy UDIMET 720 Li [15]. Once a precipitate is nucleated, its further growth is evaluated based on the evolution equations for the radius and composition of the precipitate derived by Svoboda et al [7] in a mean-field approach utilizing the thermodynamic extremal principle.…”

Section: Computer Simulationsmentioning

confidence: 99%

Numerical Simulation of the Simultaneous Precipitation of δ and γ Phases in the Ni-Base Superalloy ATI Allvac® 718Plus™

Sommitsch¹,

Kozeschnik²,

Zickler³

et al. 2010

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

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The present work deals with the numerical simulation of the precipitation kinetics of δ (Ni 3 (Nb, Al)) and γ' (Ni 3 (Al, Ti, Nb)) phases in the commercial nickel-base superalloy ATI Allvac®718Plus TM . Important precipitate parameters such as volume fraction, mean radius and number density are numerically calculated as a function of the heat treatment parameters time and temperature and compared to experimentally determined data. To match the experimentally observed kinetics, the predicted interfacial energy of the precipitates, as calculated for a sharp, planar phase boundary, is adjusted to take into account the interfacial curvature and entropic effects of a diffuse interface. Using these modified interfacial energies, the calculated results show excellent agreement with the experimental measurements. Finally, a calculated time-temperature-precipitation (TTP) diagram for concurrent δ and γ' precipitation is presented, which clearly demonstrates strong kinetic interactions during simultaneous precipitation of these phases. Thus, the present study emphasizes the importance of carefully controlling the heat treatment parameters time and temperature during the production process of ATI Allvac®718Plus TM , in order to achieve the desired microstructure and hence mechanical properties.

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Multimodal size distributions of γ′ precipitates during continuous cooling of UDIMET 720 Li

Cited by 177 publications

References 33 publications

Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

A Computational Framework for Material Design

Numerical Simulation of the Simultaneous Precipitation of δ and γ Phases in the Ni-Base Superalloy ATI Allvac® 718Plus™

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Multimodal size distributions of γ′ precipitates during continuous cooling of UDIMET 720 Li

Cited by 177 publications

References 33 publications

Influence of Both &gamma;' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Influence of Both &gamma;' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

A Computational Framework for Material Design

Numerical Simulation of the Simultaneous Precipitation of &delta; and &gamma; Phases in the Ni-Base Superalloy ATI Allvac&reg; 718Plus&trade;

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Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Influence of Both γ' Distribution and Grain Size on the Tensile Properties of UDIMET 720Li At Room Temperature

Numerical Simulation of the Simultaneous Precipitation of δ and γ Phases in the Ni-Base Superalloy ATI Allvac® 718Plus™