Effect of Thermal Exposure and Rejuvenation Treatment on Microstructure and Stress Rupture Properties of IN738LC

IN738LC 합금의 열간 노출 및 재생 열처리에 따른 미세조직과 응력 파단 특성의 변화

  • 최백규 (한국기계연구원 내열재료그룹) ;
  • 주동원 (한국기계연구원 내열재료그룹) ;
  • 김인수 (한국기계연구원 내열재료그룹) ;
  • 장중철 (한전전력연구원 발전연구실) ;
  • 조창용 (한전전력연구원 발전연구실)
  • Published : 2001.11.01

Abstract

Effects of thermal exposure and rejuvenation treatment on the microstructural evolution and the stress-rupture properties of IN738LC have been investigated. The role of precipitates on the stress-rupture properties has been analyzed through microstructural observations. Thermal exposure at $982^{\circ}C$ for 1000 hours gave rise to precipitation of $\sigma$ phase and coarsening of r'. The microstructural degradation with thermal exposure at $982^{\circ}C$ deteriorated stress rupture properties of the alloy. All the existing phases except MC carbides have completely dissolved into the matrix with homogenization treatment at $1200^{\circ}C$ for 2 hours. Microstructure and stress-rupture properties of the thermal exposed specimens have been successfully rejuvenated by the proposed treatment.

Keywords

References

  1. Y. Yoshioka, D. Saito, K. Fujiyama and N. Okabe, Advanced Materials and Coatings for Combustion Turbines, Proceeding of ASM 1993 Materials Congress Materials Week '93, Oct. 17-21, Pittsburgh, Pennsylvania, 53-58 (1993)
  2. G. Jianting, D. Ranucci, E. Picco & P. M. Strocchi : Metall. Mater. Trans. A, 14A, 2329 (1983)
  3. P. J. Henderson : Scripta Metall. 22, 1103 (1988) https://doi.org/10.1016/S0036-9748(88)80112-1
  4. R. Castillo, A.K. Koul and J-P. A. Immarigeon, in Proceedings of 6th International Symposium on Superallys (Pennsylvania, USA, September 1988). ed. Reichman et al., (The Metallurgical Society, Pennsylvania, USA, 1988) p.805
  5. J. R. Mihalisin : Trans., AIME, 239, 180 (1967)
  6. E. W. Ross and C. T. Sims, Superalloys II, p.97, ed. C. T. Sims et. al., John Wiley & Sons, New York (1987)
  7. G. S. Hoppin and T. F. Berry, Welding Research Supplement, November, 505-s (1970)
  8. D. L. Keller and W. R. Young, Cost Effective Repair Techniques for Turbine Airfoils, AFWAL-TR-81-4009, 1, June, (1981)
  9. C. Y. Su, C. P. Chou and B. C. Liu : Mat. Sci. Tech., March, 15, 316 (1999)
  10. A. J. Ardell and R. B. Nicholson : Acta Metall., 14, 1295 (1966) https://doi.org/10.1016/0001-6160(66)90247-1
  11. R. F. Decker and C. T. Sims, The superalloys, p.33, ed. C. T. Sims and W. C. Hagel, John Wiley & Sons, New York (1972)
  12. E. Balikcl, A. Raman and R. A. Mirshams : Metall. Mater. Trans. A, 28A, 1993 (1997) https://doi.org/10.1007/s11661-997-0156-9
  13. Proceedings of 8th International Symposium on Superallys D. L. Sponseller;Kissinger(ed.)(et .al.)
  14. D. L. Sponseller, in Proceedings of 8th International Symposium on Superallys (Pennsylvania, USA, September 1988). ed. Kissinger et. al. (The Metallurgical Society, Pennsylvania, USA, 1996) p.259
  15. M. McLean : Acta Metall., 33 (4), 545 (1985) https://doi.org/10.1016/0001-6160(85)90018-5
  16. B. Burton, Phil. Mag., A43, 1 (1981) https://doi.org/10.1080/01418618108239389
  17. E. Artz and M. F. Ashby, Scripta Metall., 16, 1285 (1982) https://doi.org/10.1016/0036-9748(82)90484-7
  18. R. S. W. Shewfelt and L. M. Brown, Phil. Mag., 35, 945 (1977) https://doi.org/10.1080/14786437708232636
  19. C. N. Ahlquist. and W. D. Nix, Acta Metall., 19, 373 (1971) https://doi.org/10.1016/0001-6160(71)90105-2
  20. J. D. Parker and B. Wilshire, Met. Sci., 9, 248 (1975)
  21. L. M. Brown and R. K. Ham, Strengthening Methods in Crystal, p.9, ed. A. Kelly and R. B. Nicholson. Elsevier, Amsterdam (1971)
  22. R. Labusch and R. B. Schwarz, J. Appl. Phys., 49, 5174 (1978) https://doi.org/10.1063/1.324413