Research Papers

Precipitate Microstructure as an Indicator of Stress and Temperature Distributions in a Serviced Gas Turbine Blade

[+] Author and Article Information
Mehmet Guclu Akkoyun

Department of Mechanical Engineering,
Bogazici University,
South Campus,
Bebek 34342, Istanbul, Turkey
e-mail: mehmet.akkoyun@boun.edu.tr

Ercan Balikci

Department of Mechanical Engineering,
Bogazici University,
South Campus,
Bebek 34342, Istanbul, Turkey
e-mail: ercan.balikci@boun.edu.tr

Contributed by the Materials Division of ASME for publication in the JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY. Manuscript received February 27, 2017; final manuscript received June 22, 2017; published online August 8, 2017. Assoc. Editor: Curt Bronkhorst.

J. Eng. Mater. Technol 140(1), 011001 (Aug 08, 2017) (6 pages) Paper No: MATS-17-1062; doi: 10.1115/1.4037275 History: Received February 27, 2017; Revised June 22, 2017

Superalloys are high temperature materials which are indispensable in many high temperature applications such as the gas turbines. IN738LC is a nickel-based superalloy that is extensively used in the hot sections of the gas turbines. The strengthening in this alloy is provided mainly by the γ′ precipitates. In this research, precipitate size and morphology of a serviced IN738LC polycrystalline turbine blade is investigated. Specimens from the trailing edge, middle, and leading edge positions of the tip, middle, and root sections on their hot (exterior) and cooled (interior) surfaces are analyzed for the precipitate size and morphology. The size and morphology are then linked to the temperature and stress/strain distribution in the blade. In general, the hot surfaces have larger precipitates that indicate a higher temperature exposure. In particular, the precipitate size is larger in the tip and middle sections than the root section, implying that the latter has a lower temperature. As the precipitates transforms to rafts at high temperature and stress/strain, the middle positions of the tip and middle sections, the trailing edge of the tip section, and the leading edge of the middle section are predicted to have high temperature–stress/strain coupling.

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Sims, C. T. , and Hagel, W. C. , eds., 1972, The Superalloys, Wiley-Interscience, New York.
Singh, K. , 2014, “ Advanced Materials for Land Based Gas Turbines,” Trans. Indian Inst. Met., 67(5), pp. 601–615. [CrossRef]
Muktinutalapati, N. R. , 2011, “ Materials for Gas Turbines—An Overview,” Advances in Gas Turbine Technology, InTech, Rijeka, Croatia.
Pomeroy, M. J. , 2005, “ Coatings for Gas Turbine Materials and Long Term Stability Issues,” Mater. Des., 26(3), pp. 223–231. [CrossRef]
Reed, R. C. , 2006, The Superalloys—Fundamentals and Applications, Cambridge University Press, New York. [CrossRef]
Balikci, E. , Mirshams, R. A. , and Raman, A. , 2000, “ Tensile Strengthening in the Nickel-Base Superalloy IN738LC,” J. Mater. Eng. Perform., 9(3), pp. 324–329. [CrossRef]
Lifshitz, I . M. , and Sloyozov, V. V. , 1961, “ The Kinetics of Precipitation From Supersaturated Solid Solutions,” J. Phys. Chem. Solids, 19(1–2), pp. 35–50. [CrossRef]
Wagner, C. , 1961, “ Theorie der Alterung von Niederschlagen Durch Umlosen (Ostwald-Reifung),” Z. Elektrochem., 65(7–8), pp. 581–591.
Ricks, R. A. , Porter, A. J. , and Ecob, R. C. , 1983, “ The Growth of γ’ Precipitates in Nickel-Base Superalloys,” Acta Metall., 31(1), pp. 43–53. [CrossRef]
Tian, S. G. , Zhou, H. H. , Zhang, J. H. , Yang, H. C. , Xu, Y. B. , and Hu, Z. Q. , 2000, “ Directional Coarsening of γ’ Phase in Single Crystal Nickel Based Superalloys During Tensile Creep,” Mater. Sci. Technol., 16(4), pp. 451–456. [CrossRef]
Sugui, T. , Shu, Z. , Fushun, L. , Anan, L. , and Jingjing, L. , 2011, “ Microstructure Evolution and Analysis of a Single Crystal Nickel-Based Superalloy During Compressive Creep,” Mater. Sci. Eng. A, 528(15), pp. 4988–4993. [CrossRef]
Zhao, K. , Ma, Y. H. , Lou, L. H. , and Hu, Z. Q. , 2005, “ Directional Coarsening of γ’ Phase Induced by Phase Transformation Stress,” J. Mater. Res., 20(9), pp. 2314–2321. [CrossRef]
Balikci, E. , Raman, A. , and Mirshams, R. A. , 1997, “ Influence of Various Heat Treatments on the Microstructure of Polycrystalline IN738LC,” Metall. Mater. Trans. A, 28(10), pp. 1993–2003. [CrossRef]
Miura, N. , Nakata, K. , Miyazaki, M. , Hayashi, Y. , and Kondo, Y. , 2010, “ Morphology of γ’ Precipitates in Second Stage High Pressure Turbine Blade of Single Crystal Nickel-Based Superalloy After Serviced,” Mater. Sci. Forum, 638–642, pp. 2291–2296. [CrossRef]
Miura, N. , Harada, N. , Kondo, Y. , and Matsuo, T. , 2002, “ Morphological Changes in γ’ Phase in Different Portions of First Stage High Pressure Turbine Blade of PWA 1480,” Seventh Conference Materials for Advanced Power Engineering, Jülich, Germany, Jan. 1, pp. 245–254.
Biermann, H. , Spangel, S. , and Mughrabi, H. , 1996, “ Local Lattice Parameter Changes in Monocrystalline Turbine Blades Subjected to Service-Like Conditions,” Int. J. Mater. Res., 87(5), pp. 403–410.
Biermann, H. , von Grossmann, B. , Schneider, T. , Feng, H. , and Mughrabi, H. , 1996, “ Investigation of the γ/γ' Morphology and Internal Stresses in a Monocrystalline Turbine Blade After Service: Determination of the Local Thermal and Mechanical Loads,” Eighth International Symposium on Superalloys, Champion, PA, Sept. 22–26, pp. 201–210. http://www.tms.org/superalloys/10.7449/1996/Superalloys_1996_201_210.pdf
Epishin, A. , Link, T. , Nazmy, M. , Staubli, M. , Klingelhöffer, H. , and Nolze, G. , 2008, “ Microstructural Degradation of CMSX-4: Kinetics and Effect on Mechanical Properties,” 11th International Symposium Superalloys, Champion, PA, Sept. 14–18, pp. 725–731.
Rasband, W. S. , 1997, “ ImageJ,” U. S. National Institutes of Health, Bethesda, MA, accessed July 21, 2017, https://imagej.nih.gov/ij/
Balikci, E. , and Raman, A. , 2000, “ Characteristics of the γ′ Precipitates at High Temperatures in Ni-Base Polycrystalline Superalloy IN738LC,” J. Mater. Sci., 35(14), pp. 3593–3597. [CrossRef]
Balikci, E. , Ferrell, R. E. , and Raman, A. , 1999, “ Preferred Orientations in the Superalloy IN738LC After Different Aging Heat Treatments,” Z. Metall., 90(2), pp. 141–146. https://inis.iaea.org/search/search.aspx?orig_q=RN:30017335
Altincekic, A. , and Balikci, E. , 2014, “ Precipitate Rafting in a Polycrystalline Superalloy During Compression Creep,” Metall. Mater. Trans. A, 45(13), pp. 5923–5936. [CrossRef]
Altincekic, A. , and Balikci, E. , 2013, “ Precipitate Size in the Superalloy IN738LC During Compression Creep,” Metall. Mater. Trans. A, 44(6), pp. 2487–2498. [CrossRef]
Balikci, E. , and Erdeniz, D. , 2010, “ Multimodal Precipitation in the Superalloy IN738LC,” Metall. Mater. Trans. A, 41(6), pp. 1391–1398. [CrossRef]
Roy, I. , Balikci, E. , Ibekwe, S. , and Raman, A. , 2005, “ Precipitate Growth Activation Energy Requirements in the Duplex Size γ′ Distribution in the Superalloy IN738LC,” J. Mater. Sci., 40(23), pp. 6207–6215. [CrossRef]


Grahic Jump Location
Fig. 1

Pressure side of the serviced turbine blade

Grahic Jump Location
Fig. 2

A representative mount for tip section-middle position specimens. The cube on the right schematically shows sample planes. The cooling channel is between the planes “suction cold” and “pressure cold.”

Grahic Jump Location
Fig. 3

Precipitate size for specimens in the tip, middle, and root sections. PT, pressure side-trailing edge; PM, pressure side-middle; PL, pressure side-leading edge; OL, stagnation point; SL, suction side-leading edge; SM, suction side-middle; ST, suction side-trailing edge.

Grahic Jump Location
Fig. 7

Precipitate morphology in the firtree specimen

Grahic Jump Location
Fig. 6

Precipitate morphology in the root section. The scale bar is only for the precipitates, and the blade outline is not to scale.

Grahic Jump Location
Fig. 5

Precipitate morphology in the middle section. The scale bar is only for the precipitates, and the blade outline is not to scale.

Grahic Jump Location
Fig. 4

Precipitate morphology in the tip section. The scale bar is only for the precipitates, and the blade outline is not to scale.



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