Deformation mechanism and microstructure evolution of spray formed GH738 alloy fabricated by hot extrusion

WANG Yue1 XU Wenyong1 LIU Na1 ZHENG Liang1 YUAN Hua1 LI Zhou1 ZHANG Guoqing1

(1.Science and Technology on Advanced High Temperature Structural Materials Laboratory, AECC Beijing Institute of Aeronautical Materials, Beijing, China 100095)

【Abstract】The research on hot deformation including flow behavior, microstructure evolution via EBSD method, and the constitutive characteristic model of the spray formed GH738 alloy fabricated by hot extrusion is conducted using Gleeble-3500TM simulator in the temperature range of 950 °C–1 150 °C, strain rate range of 0.001–1 s−1, and engineering strain of 50%. The results show that the flow stress decreases with the increase in the deformation temperature and the decrease in the strain rate. The peak flow stress of the as-forged GH738 alloy with coarse grains is higher than that of the spray formed GH738 alloy with fine grains fabricated by hot extrusion. The activation energy Q of the latter is 651.08 kJ·mol−1 and its activation energy Q of hot deformation is tending to increase with the decrease in the as-received average grain size. The microstructure evolves from the as-received stretched grains to equiaxed grains with the increasing deformation temperature through the onset of recrystallization. The fully dynamic recrystallization microstructure is obtained at the temperature above 1 000 °C and the microstructure tends to coarsen with the higher deformation temperature.

【Keywords】 GH738 superalloy; spray forming; hot extrusion; constitutive equation of hot deformation; recrystallization microstructure;


【Funds】 National Key R&D Project of China (2017YFB0305800) National Natural Science Foundation of China (51304177)

Download this article


    [1] DONG J X. Superalloy GH738 and its applications [M]. Beijing: Metallurgical Industry Press, 2014 (in Chinese).

    [2] YAO Z H, ZHANG M C, DONG J X. Stress rupture fracture model and microstructure evolution for waspaloy [J]. Metallurgical and Materials Transactions A, 2013, 44 (7): 3084–3098.

    [3] CHAMANFAR A, JAHAZI M, GHOLIPOUR J, et al. Evolution of flow stress and microstructure during isothermal compression of waspaloy [J]. Materials Science & Engineering: A, 2014, 615: 497–510.

    [4] AMIRI A, BRUSCHI S, SADEGHI M H, et al. Investigation on hot deformation behavior of waspaloy [J]. Materials Science & Engineering: A, 2013, 562: 77–82.

    [5] WANG L, YANG G, LEI T, et al. Hot deformation behavior of GH738 for A-USC turbine blades [J]. Journal of Iron and Steel Research, International, 2015, 22 (11): 1043–1048.

    [6] YAO Z H, DONG J X, ZHANG M C. Microstructure control and prediction of GH738 superalloy during hot deformation I construction of microstructure evolution model [J]. Acta Metallurgica Sinica, 2011, 47 (12): 1581–1590 (in Chinese with English abstract).

    [7] CHEN S T, WANG J, HU D X. Hot compression behaviors of double cone samples of GH738 alloy [J]. Transactions of Materials and Heat Treatment, 2016, 37 (12): 80–85 (in Chinese with English abstract).

    [8] WANG Y, XU W Y, LIU N, et al. Deformation characteristic and microstructure evolution of spray formed GH738 alloy [J]. Rare Metal Materials and Engineering, 2018, 47 (3): 878–883 (in Chinese with English abstract).

    [9] PAN C C, LI D G, LING G, et al. Model for flow stress of Fe-15Cr-25Ni superalloy under hot compression [J]. Journal of Materials Engineering, 2005 (6): 7–10 (in Chinese with English abstract).

    [10] LI Q, GUO H Z, WANG Y W, et al. Hot deformation behaviors and microstructure evolution of GH4049 alloy [J]. Journal of Materials Engineering, 2014 (12): 55–59 (in Chinese with English abstract).

    [11] WU K, LIU G Q, HU B F, et al. Research on high temperature deformation behavior of new type nickel-based P/M superalloy [J]. Journal of Aeronautical Materials, 2010, 30 (4): 1–7 (in Chinese with English abstract).

    [12] PU E X, ZHENG W J, SONG Z G, et al. Hot deformation characterization of nickel-based superalloy UNS10276 through processing map and microstructural studies [J]. Journal of Alloys and Compounds, 2017, 694: 617–631.

    [13] HE G A, DING H H, LIU C Z, et al. Effects of powder characteristics on microstructure and deformation activation energy of nickel based superalloy [J]. The Chinese Journal of Nonferrous Metals, 2016, 26 (1): 37–49 (in Chinese with English abstract).

    [14] LI L X, TANG L, ZHOU J L, et al. Influence of carbon content and grain size on activation energy of microalloy steel [J]. Special Steel, 2003, 24 (3): 24–26 (in Chinese with English abstract).

    [15] YAO Z H, DONG J X, ZHANG M C. Hot deformation behavior of superalloy GH738 [J]. Rare Metal Materials and Engineering, 2013, 42 (6): 1199–1204 (in Chinese with English abstract).

This Article


CN: 11-3159/V

Vol 40, No. 02, Pages 1-7

April 2020


Article Outline


  • 1 Experimental materials and methods
  • 2 Results and analysis
  • 3 Conclusions
  • References