Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Solidification Structure of Superalloy René 80 and Variation of Tensile Properties after Heat-Treatment

초내열합금 René 80의 응고 조직과 열처리 후 인장특성의 변화

  • Woo, Hanbyeol (R&D Center, Seah Changwon Special Steel Co. Ltd.) ;
  • Shin, Jongho (R&D Center, Doosan Heavy Industries & Construction Co. Ltd.) ;
  • Joo, Yunkon (Department of Materials Science and Engineering, Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University) ;
  • Lee, Jehyun (Department of Materials Science and Engineering, Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University)
  • 우한별 (세아창원특수강(주) 기술연구소) ;
  • 신종호 (두산중공업(주) 기술연구소) ;
  • 주윤곤 (창원대학교 신소재공학부) ;
  • 이재현 (창원대학교 신소재공학부)
  • Received : 2020.10.04
  • Accepted : 2020.11.14
  • Published : 2020.12.27
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Abstract

Microstructural characteristics of directionally solidified René 80 superalloy are investigated with optical microscope and scanning electron microscope; solidification velocity is found to change from 25 to 200 μm/s under the condition of constant thermal gradient (G) and constant alloy composition (Co). Based on differential scanning calorimetry (DSC) measurement, γ phase (1,322 ℃), MC carbide (1,278 ℃), γ/γ' eutectic phase (1,202 ℃), and γ' precipitate (1,136 ℃) are formed sequentially during cooling process. The size of the MC carbide and γ/γ' eutectic phases gradually decrease with increasing solidification velocity, whereas the area fractions of MC carbide and γ/γ' eutectic phase are nearly constant as a function of solidification velocity. It is estimated that the area fractions of MC carbide and γ/γ' eutectic phase are determined not by the solidification velocity but by the alloy composition. Microstructural characteristics of René 80 superalloy after solid solution heat-treatment and primary aging heat-treatment are such that the size and the area fraction of γ' precipitate are nearly constant with solidification velocity and the area fraction of γ/γ' eutectic phase decreases from 1.7 % to 0.955 %, which is also constant regardless of the solidification velocity. However, the size of carbide solely decreases with increasing solidification velocity, which influences the tensile properties at room temperature.

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References

  1. J. Tiley, G. Viswanathan, J. Hwang, A. Shiveley and R. Banerjee, Mater. Sci. Eng., A, 528, 32 (2010). https://doi.org/10.1016/j.msea.2010.07.036
  2. M. Afhaie-Khafri and M. Hajjavady, Mater. Sci. Eng., A, 487, 388 (2008). https://doi.org/10.1016/j.msea.2007.11.010
  3. R. Sidhu, O. Ojo and M. Chaturvedi, J. Mater. Sci., 43, 3612 (2008). https://doi.org/10.1007/s10853-008-2575-4
  4. Y. Xu, Q. Jin, X. Xiao, X. Cao, G. Jia and Y. Zhu, Mater. Sci. Eng., A, 528, 4600 (2011). https://doi.org/10.1016/j.msea.2011.02.072
  5. Y. Xu, C. Yang, X. Xiao, X. Cao, G. Jia and Z. Shen, Mater. Sci. Eng., A, 530, 315 (2011). https://doi.org/10.1016/j.msea.2011.09.091
  6. S. Kwon, J. Shin, G. Rim, G. Sung, B. Yoon, E. Jung and J. Lee, Korean J. Met. Mater., 56, 745 (2018). https://doi.org/10.3365/KJMM.2018.56.10.745
  7. C. Wei, H. Bor and L. Chang, Mater. Sci. Eng., A, 527, 3741 (2010). https://doi.org/10.1016/j.msea.2010.03.053
  8. J. Safari and S. Nategh, J. Mater. Process. Technol., 176, 240 (2006). https://doi.org/10.1016/j.jmatprotec.2006.03.165
  9. F. L. Versnyder and M. E. Shank, Mater. Sci. Eng., 6, 213 (1970). https://doi.org/10.1016/0025-5416(70)90050-9
  10. J. D. Hunt, Int. Conf. Solidification and Casting of Metals, p. 3, Metals Society, London (1979).
  11. W. Kurz and D. J. Fisher, Acta Metall., 29, 11 (1981). https://doi.org/10.1016/0001-6160(81)90082-1
  12. R. Trivedi, Metall. Trans. A, 15, 977 (1984). https://doi.org/10.1007/BF02644689
  13. T. F. Bower, H. D. Brody and M. C. Flemings, Trans. Met. Soc. AIME, 236, 624 (1966).
  14. J. S. Langer, Rev. Mod. Phys., 52, 1 (1980). https://doi.org/10.1103/RevModPhys.52.1
  15. C. Yang, Y. Xu, H. Nie, X. Xiao, G. Jia and Z. Shen, Mater. Des., 43, 66 (2013). https://doi.org/10.1016/j.matdes.2012.06.039