Co기 초합금 ECY768에서 응고 조직 및 탄화물 형성 거동

이정석; 김현철; 이재현; 서성문; 조창용; J.S. Lee; H.C. Kim; J.H. Lee; S.M. Seo; C.Y. Jo

Korean Journal of Materials Research, Vol.13, No.6, 381-388, June, 2003

DOI10.3740/MRSK.2003.13.6.381 Export Citation

Co기 초합금 ECY768에서 응고 조직 및 탄화물 형성 거동

Solidification Microstructure and Carbide Formation behaviors in the Co-base Superalloy ECY768

이정석, 김현철, 이재현 ^†, 서성문 ¹, 조창용 ¹

창원대학교 금속재료공학과
¹한국 기계연구원 내열재료그룹

J.S. Lee, H.C. Kim, J.H. Lee^†, S.M. Seo¹, and C.Y. Jo¹

Department of Metallurgy and Materials Science, Changwon National University, Korea
¹High Temperature Materials Group, Korea Institute of Machinery and Materials, Korea

E-mail:

Directional solidification experiments were carried out at 0.5-150 μm /s in the Co-base superalloy ECY 768. As increasing solidification rate, the dendrite length increased and it reached the maximum at 150 μm /s, where the tip temperature is close to the liquidus. The liquidus and eutectic temperatures could be estimated by comparing the dendrite lengths and the temperature gradients at the solid/liquid interface and those were estimated as 1424.6 ? C and 1343 ? C respectively. Between the dendrites just below final freezing temperature, MC carbide and M 23 C 6 carbide were found. It was confirmed that the script or blocky shape was Ta or W-rich MC carbide, and the lamellar shape was Cr-rich eutectic carbide. The solid/liquid interface morphology clearly showed that the Cr-rich eutectic carbide formed just after the script type MC carbide.

Keywords:Cobalt-base superalloy;Directional solidification;Solidification microstructure;Solidification rate;Carbide

[References]

Brooks CR, Heat Treatment, Sturcture and Properties of Nonfeffous Alloys, US (1982) (1982)
ASM Specialty Handbook, Heat-Resistant Materials, ASM Inter. (1977) (1977)
ASM Specialty Handbook, Nickel, Cobalt, and Their Alloys, ASM Inter. (2000) (2000)
Sims CT, Stoloff NS, Hagel WG, Superalloys II, John Wiley & Sons (1987) (1987)
Lee JH, Verhoeven JD, J. Phase Equilibria, 15(2), 136 (1994)
Dharwadkar SR, Hilpert K, Schubert J, Venugopal V, Zeitshrigt fur Metallkunde, 9, 744 (1992)
예대희, 김현철, 이재현, 유영수, 조창용, 한국재료학회지, 12(12), 897 (2002) (2002)
배재식, 김현철, 이재현, 유영수, 조창용, 한국재료학회지, 11(6), 50 (2002) (2002)
Lee JH, Seo SM, Kim DH, Choe SJ, Kim HM, Liquid Metal Processing & Casting, American Vacuum Society, 54 (1999) (1999)
김현철, 이재현, 서성문, 김두현, 조차용, 한국재료학회지, 11, 721 (2001) (2001)
Verhoeven JD, Fundamentals of Physical Metallurgy, John Wiley & Sons (1987) (1987)
McLean M, Directionally Solidification Material for High Temperature Service, The Metals Society (1983) (1983)

[Related Articles]

[1] Brooks CR, Heat Treatment, Sturcture and Properties of Nonfeffous Alloys, US (1982) (1982)

[2] ASM Specialty Handbook, Heat-Resistant Materials, ASM Inter. (1977) (1977)

[3] ASM Specialty Handbook, Nickel, Cobalt, and Their Alloys, ASM Inter. (2000) (2000)

[4] Sims CT, Stoloff NS, Hagel WG, Superalloys II, John Wiley & Sons (1987) (1987)

[5] Lee JH, Verhoeven JD, J. Phase Equilibria, 15(2), 136 (1994)

[6] Dharwadkar SR, Hilpert K, Schubert J, Venugopal V, Zeitshrigt fur Metallkunde, 9, 744 (1992)

[7] 예대희, 김현철, 이재현, 유영수, 조창용, 한국재료학회지, 12(12), 897 (2002) (2002)

[8] 배재식, 김현철, 이재현, 유영수, 조창용, 한국재료학회지, 11(6), 50 (2002) (2002)

[9] Lee JH, Seo SM, Kim DH, Choe SJ, Kim HM, Liquid Metal Processing & Casting, American Vacuum Society, 54 (1999) (1999)

[10] 김현철, 이재현, 서성문, 김두현, 조차용, 한국재료학회지, 11, 721 (2001) (2001)

[11] Verhoeven JD, Fundamentals of Physical Metallurgy, John Wiley & Sons (1987) (1987)

[12] McLean M, Directionally Solidification Material for High Temperature Service, The Metals Society (1983) (1983)