Research Papers: Gas Turbines: Manufacturing, Materials, and Metallurgy

High-Temperature Deformation of Inconel 718PlusTM

[+] Author and Article Information
Utkudeniz Ozturk

Polytechnic University of Catalonia,
Av. Diagonal, 647,
Barcelona 08028, Spain
e-mail: utkudeniz.ozturk@upc.edu

Jose Maria Cabrera, Jessica Calvo

Centre Tecnologic Manresa (CTM),
Plaza de la Ciencia, 2, Manresa,
Barcelona 08242, Spain;
Polytechnic University of Catalonia,
Av. Diagonal, 647,
Barcelona 08028, Spain

1Corresponding author.

Contributed by the Manufacturing Materials and Metallurgy Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received June 20, 2016; final manuscript received July 27, 2016; published online October 11, 2016. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(3), 032101 (Oct 11, 2016) (7 pages) Paper No: GTP-16-1243; doi: 10.1115/1.4034539 History: Received June 20, 2016; Revised July 27, 2016

Since its introduction in 2003, alloy 718PlusTM spurred a lot of interest owing to its increased maximum service temperature over conventional Inconel 718 (704 °C versus 650 °C), good formability, and weldability together with its moderate cost. Understanding the high-temperature deformation characteristics and microstructural evolution is still of interest to many. It is known that the service performance and hot-flow behavior of this alloy are a strong function of the microstructure, particularly the grain size. To develop precise microstructure evolution models and foresee the final microstructure, it is important to understand how and under which forming conditions softening and precipitation processes occur concurrently. In this work, the softening behavior, its mechanisms, and the precipitation characteristics of 718PlusTM were investigated in two parallel studies. While cylindrical compression tests were employed to observe the hot-flow behavior, the precipitation behavior and other microstructural phenomena such as particle coarsening were tracked via hardness measurements. A precipitation–temperature–time (PTT) diagram was reported, and modeling of the flow curves via hyperbolic sine model was discussed in the light of the PTT behavior. Both “apparent” approach and “physically based” approach are implemented and two different sets of parameters were reported for the latter. Finally, recovery and recrystallization kinetics are described via Estrin–Mecking and Bergstrom, and Avrami kinetics, respectively.

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Eiselstein, H. L. , 1962, “ Age-Hardenable Nickel Alloy,” U.S. Patent No. 3,046,108. https://www.google.com/patents/US3046108
Kennedy, R. , 2005, “ Allvac 718PlusTM, Superalloy for the Next Forty Years,” Superalloys 718, 625, 706, and Derivatives.
Ott, E. A. , Groh, J. , and Sizek, H. , 2005, “ Metals Affordability Initiative: Application of Allvac Alloy 718PlusTM for Aircraft Engine Static Structural Components,” Superalloys 718, 625, 706, and Derivatives.
Cao, W.-D. , 2005, “ Solidification and Solid State Phase Transformation of Allvac 718PlusTM Alloy,” Sixth International Special Emphasis Symposium on Superalloys 718, 625, 706 and Derivatives, pp. 165–177. https://www.atimetals.com/products/718plus-alloy/Documents/165.pdf
Xie, X. , Dong, G. W. J. , Xu, C. , Cao, W.-D. , and Kennedy, R. , 2005, “ Structure Stability Study on a Newly Developed Nickel-Base Superalloy-Allvac 718PlusTM,” Sixth International Special Emphasis Symposium on Superalloys 718, 625, 706 and Derivatives, pp. 179–191. https://www.atimetals.com/products/718plus-alloy/Documents/179.pdf
Xie, X. , Xu, C. , Wang, G. , Dong, J. , Cao, W. , and Kennedy, R. , 2005, “ TTT Diagram of a Newly Developed Nickel-Base Superalloy-Allvac 718PlusTM,” Sixth International Symposium on Superalloys 718, 625, 706 and Derivatives 2005, The Minerals, Metals & Materials Society, Warrendale, PA, pp. 193–202. https://www.atimetals.com/products/718plus-alloy/Documents/193.pdf
Cozar, R. , and Pineau, A. , 1973, “ Morphology of γ′ and γ″ Precipitates and Thermal Stability of Inconel 718 Type Alloys,” Metall. Trans., 4(1), pp. 47–59. [CrossRef]
Viskari, L. , and Stiller, K. , 2011, “ Atom Probe Tomography of Ni-Base Superalloys Allvac 718Plus and Alloy 718,” Ultramicroscopy, 111(6), pp. 652–658. [CrossRef] [PubMed]
Casanova, A. , Martín-Piris, N. , Hardy, M. , and Rae, C. , 2014, “ Evolution of Secondary Phases in Alloy ATI 718PlusTM During Processing,” MATEC Web Conf., 14, p. 09003. [CrossRef]
Cao, W. , and Kennedy, R. , 2004, “ Role of Chemistry in 718-Type Alloys—Allvac 718PlusTM Alloy Development,” Superalloys 2004, The Minerals, Metals & Materials Society, Warrendale, PA, pp. 91–99. http://alleghenytechnologies.com/products/718plus-alloy/Documents/Defense11a_04_576X_91.pdf
Stotter, C. , Sommitsch, C. , Wagner, J. , Leitner, H. , Letofsky-Papst, I. , Zickler, G. A. , Prantl, W. , and Stockinger, M. , 2008, “ Characterization of δ-Phase in Superalloy Allvac 718PlusTM,” Int. J. Mater. Res., 99(4), pp. 376–380. [CrossRef]
Pickering, E. , Mathur, H. , Bhowmik, A. , Messé, O. , Barnard, J. , Hardy, M. , Krakow, R. , Loehnert, K. , Stone, H. , and Rae, C. , 2012, “ Grain-Boundary Precipitation in Allvac 718Plus,” Acta Mater., 60(6), pp. 2757–2769. [CrossRef]
Si, J.-y. , Liao, X.-h. , Xie, L.-q. , and Lin, K.-r. , 2015, “ Flow Behavior and Constitutive Modeling of Delta-Processed Inconel 718 Alloy,” J. Iron Steel Res. Int., 22(9), pp. 837–845. [CrossRef]
Huber, D. , Stotter, C. , Sommitsch, C. , Mitsche, S. , Poelt, P. , Buchmayr, B. , and Stockinger, M. , 2008, “ Microstructure Modeling of the Dynamic Recrystallization Kinetic During Turbine Disc Forging of the Nickel Based Superalloy Allvac 718PlusTM,” 11th International Symposium on Superalloys, pp. 855–861. http://www.tms.org/superalloys/10.7449/2008/superalloys_2008_855_861.pdf
Sellars, C. M. , and Tegart, W. M. , 1966, “ Relationship Between Strength and Structure in Deformation at Elevated Temperatures,” Mem. Sci. Rev. Metall., 63(9), pp. 731–745.
Sellars, C. M. , and McTegart, W. J. , 1966, “ On the Mechanism of Hot Deformation,” Acta Metall., 14(9), pp. 1136–1138. [CrossRef]
Cabrera, J. , Jonas, J. , and Prado, J. , 1996, “ Flow Behaviour of Medium Carbon Microalloyed Steel Under Hot Working Conditions,” Mater. Sci. Technol., 12(7), pp. 579–585. [CrossRef]
Frost, H. J. , and Ashby, M. F. , 1982, Deformation Mechanism Maps: The Plasticity and Creep of Metals and Ceramics, Pergamon Press, Oxford, UK.
Srinivasan, D. , Lawless, L. U. , and Ott, E. A. , 2012, “ Experimental Determination of TTT Diagram for Alloy 718PlusTM,” 12th International Symposium on Superalloys, pp. 759–768.
Mirzadeh, H. , Cabrera, J. M. , and Najafizadeh, A. , 2012, “ Modeling and Prediction of Hot Deformation Flow Curves,” Metall. Mater. Trans. A, 43(1), pp. 108–123. [CrossRef]
Mirzadeh, H. , Cabrera, J. , Prado, J. , and Najafizadeh, A. , 2011, “ Hot Deformation Behavior of a Medium Carbon Microalloyed Steel,” Mater. Sci. Eng.: A, 528(10), pp. 3876–3882. [CrossRef]
Mirzadeh, H. , Cabrera, J. M. , and Najafizadeh, A. , 2011, “ Constitutive Relationships for Hot Deformation of Austenite,” Acta Mater., 59(16), pp. 6441–6448. [CrossRef]
Suave, L. M. , Cormier, J. , Villechaise, P. , Soula, A. , Hervier, Z. , Bertheau, D. , and Laigo, J. , 2014, “ Microstructural Evolutions During Thermal Aging of Alloy 625: Impact of Temperature and Forming Process,” Metall. Mater. Trans. A, 45(7), pp. 2963–2982. [CrossRef]
Suave, L. M. , Cormier, J. , Bertheau, D. , Villechaise, P. , Soula, A. , Hervier, Z. , and Hamon, F. , 2016, “ High Temperature Low Cycle Fatigue Properties of Alloy 625,” Mater. Sci. Eng.: A, 650, pp. 161–170. [CrossRef]
Thomas, A. , El-Wahabi, M. , Cabrera, J. , and Prado, J. , 2006, “ High Temperature Deformation of Inconel 718,” J. Mater. Process. Technol., 177(1), pp. 469–472. [CrossRef]
Laasraoui, A. , and Jonas, J. , 1991, “ Prediction of Steel Flow Stresses at High Temperatures and Strain Rates,” Metall. Trans. A, 22(7), pp. 1545–1558. [CrossRef]
El Wahabi, M. , Cabrera, J. , and Prado, J. , 2003, “ Hot Working of Two AISI 304 Steels: A Comparative Study,” Mater. Sci. Eng.: A, 343(1), pp. 116–125. [CrossRef]
Christian, J. W. , 2002, The Theory of Transformations in Metals and Alloys, Elsevier, Oxford, UK.
Cabrera, J. M. , 1995, “ Caracterización mecánico-metalúrgica de la conformación en caliente del acero microaleado de medio carbono 38 MnSiVS5,” Ph.D. thesis, Departamento de Ciencia de Materiales e Ingeniería Metalúrgica, Universitat Politécnica de Catalunya, Barcelona, Spain.


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Fig. 1

Experimentally determined TTT diagram of alloy 718PlusTM [6]

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Fig. 2

Raw data, smoothing, and polynomial fitting

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Fig. 3

Temperature variation during 1000 °C tests for different strains

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Fig. 4

PTT diagram of 718PlusTM. Red line denotes 245 HV limit.

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Fig. 5

Selected flow curves

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Fig. 6

Experimentally determined TTT diagram of 718PlusTM showing only δ precipitation [11]

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Fig. 7

(a)–(g) Plots that are used to retrieve material constants of apparent approach, (h) plot to determine α′ and B in physically based approach, and (i) comparison of resulting peak stresses with the experimental values

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Fig. 8

Softening and hardening parameters versus Zener–Hollomon parameter

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Fig. 9

Curves used to determine the DRX kinetics. Top to bottom: 950 °C, 1000 °C, and 1050 °C.

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Fig. 10

Dependence of K on Zener–Hollomon parameter




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