Browse > Article
http://dx.doi.org/10.7777/jkfs.2015.35.6.170

Variation of Alloying Element Distribution and Microstructure due to Microsegregation in Ni-base Superalloy GTD 111  

Choi, Baig-Gyu (High Temperature Materials Department, Korea Institute of Materials Science)
Kim, In-Soo (High Temperature Materials Department, Korea Institute of Materials Science)
Do, Jeong-Hyeon (High Temperature Materials Department, Korea Institute of Materials Science)
Jung, Joong-Eun (High Temperature Materials Department, Korea Institute of Materials Science)
Jo, Chang-Yong (High Temperature Materials Department, Korea Institute of Materials Science)
Publication Information
Journal of Korea Foundry Society / v.35, no.6, 2015 , pp. 170-177 More about this Journal
Abstract
Segregation during solidification and homogenization during thermal exposure in GTD 111 were investigated. The microstructures of as-cast, standard heat-treated, and thermally exposed specimens were observed by SEM. A compositional analysis of each specimen was conducted by EDS. The dendrite core was enriched in W and Co, though lower levels of Ti and Ta were observed. An unexpected phase, in this case like the ${\eta}$ phase, was observed due to segregation near the ${\gamma}-{\gamma}^{\prime}$ eutectic in the standard heat-treated specimen. Segregation also induced microstructural evolution near the ${\gamma}-{\gamma}^{\prime}$ eutectic during the standard heat treatment. A quantitative analysis and microstructural observations showed that the thermal exposure at a high temperature enhanced the chemical homogeneity of the alloy.
Keywords
Ni-base superalloy; Segregation; Thermal exposure; Homogenization;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Sims CT, Stoloff NS, Hagel WC, Superalloys II, John Wiley & Sons, New York (1987).
2 Reed RC, The Superalloys, Cambridge University Press, Cambridge (2006).
3 H. E. Collins, Metall. Trans., "The Effect of Thermal Exposure on the Microstructure and Mechanical Properties of Nickel-Base Superalloys", 5 (1974) 189-204.
4 Nazmy N and Staubli M, Scripta Metall. Mater., "Embrittlement of several nickel-base alloys after high-temperature exposure", 24 (1990) 135-138.   DOI
5 Collins HE, Metall. Trans. A, "The effect of thermal exposure on the mechanical properties of the directionally solidified superalloy TRW-NASA VIA", 6A (1975) 515-530.
6 Daleo JA and Wilson JR, J. Eng. Gas Turbines Power, "GTD111 Alloy Material Study", 120 (1998) 375-382.   DOI
7 Sajjadi SA and Natech S, Mater. Sci. Eng. A, "A high temperature deformation mechanism map for the high performance Ni-base superalloy GTD-111" 307 (2001) 158-164.   DOI
8 Sajjadi SA, Natech S and Guthrie RIL, Mater. Sci. Eng. A, "Study of microstructure and mechanical properties of high performance Ni-base superalloy GTD-111", 325 (2002) 484-489.   DOI
9 Natech S and Sajjadi SA, Mater. Sci. Eng. A, "Dislocation network formation during creep in Ni-base superalloy GTD-111" 339 (2003) 103-108.   DOI
10 Cheruvu NS, Proc. 2000 International Joint Power Generation Conference, "Oxidation and Gamma Particle Coarsening Behavior of IN-738 and GTD-111DS", American Society of Mechanical Engineers, Miami (2000) 551-558.
11 Kearsey RM, Beddoes JC, Jones P and Au P, Intermetallics, "Compositional design considerations for microsegregation in single crystal superalloy systems", 12 (2004) 903-910.   DOI
12 M. J. Starink and R. C. Thomson, J. Mater. Sci., "The effect of high temperature exposure on dendritic segregation in a conventionally cast Ni based superalloy", 36 (2001) 5603-5608.   DOI
13 M. Durand-Charre, The Microstructue of Superalloys, Gordon and Breach Science Pub., Amsterdam (1997).
14 Choi BG, Kim IS, Kim DH and Jo CY, Mater. Sci. Eng. A, "Temperature dependence of MC decomposition behavior in Ni-base superalloy GTD 111", 478 (2008) 329-335.   DOI
15 Chen QZ, Jones CN and Knowles DM, Scripta Mater., "Effect of alloying chemistry on MC carbide morphology in modified RR2072 and RR2086 SX superalloys" 47 (2002) 669-675.   DOI
16 Starink MJ, Cama H and Thomson RC, Scripta Mater., "MC Carbides in the Hf Containing Ni Based Superalloy MarM002" 38 (1998) 73-80.
17 Chen J, Lee JH, Jo CY, Choe SJ and Lee YT, Mater. Sci. Eng. A, "MC carbide formation in directionally solidified MARM247 LC superalloy", 247 (1998) 113-125.   DOI
18 Poerter DA and Easterking KE, Phase Transformation in Metals and Alloys, Chapman & Hall, London (1992).