Morphological Evolution of Carbides in DZ125 Superalloy during Heat Treatment

Abstract:

Morphological evolution of carbides in DZ125 superalloy during heat treatment was investigated by using SEM and EDS. The results show that in DZ125 directionally solidified superalloy, the MC carbide is either smooth platelet or bone-shaped structure with nodes in morphology in as-cast state, which is rich in Ta, Ti and Hf. During solid solution treatment, parts of primary MC carbides dissolve, so that the morphology of MC carbide changes from smooth and regular surface to scattered configuration. During aging heat treatment and long term aging, the secondary MC carbides enriched in Hf element precipitated from the matrix. Moreover, there is some M₆C carbide enriched in W element precipitated on the grain boundary. With the process of heat treatment, the content of Hf element in MC carbides increases obviously.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1153-1158
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1153
• Online since: November 2016
• Authors: Li Rong Liu*, Shuo Han, Yi Fan Pu, Zhi Jiang Peng, Ming Jun Zhang
• Keywords: Carbides, DZ125 Superalloy, Heat Treatment, Morphology

References

[1] Starink MJ, Cama H, Thomson RC. MC carbides in the Hf containing Ni based superalloy MarM002. Scripta Mater. 38 (1997): 73-80.

DOI: 10.1016/s1359-6462(97)00409-0

[2] Bae JS, Lee JH, Kim SS, Jo CY. Formation of MC-γ/γ' eutectic fibers and their effect on stress rupture behavior in D/S Mar-M247LC superalloy. Scripta Mater., 45(2001): 503-508.

DOI: 10.1016/s1359-6462(01)01049-1

[3] Liu L, Sommer F, Fu HZ. Effect of solidification conditions of MC carbides in a nickel-base superalloy in 738 LC. Scripta Metall Mater, 30(1994): 587 -591.

DOI: 10.1016/0956-716x(94)90434-0

[4] Chen J, Lee JH, Jo CY, et al. MC carbide formation in directionally solidified MAR-M247 LC superalloy Mater. Sci. Eng. A, 247(1998): 113-125.

DOI: 10.1016/s0921-5093(97)00761-2

[5] Zheng L, Gu CQ, Zheng YR. Investigation of the solidification behavior of a new Ru-containing cast Ni-base superalloy with high W content. Scripta Mater., 50(2004): 435-439.

DOI: 10.1016/j.scriptamat.2003.11.009

[6] Chen QZ, Jones CN, Knowles DM. Effect of alloying chemistry on MC carbide morphology in modified RR2072 and RR2086 SX superalloys. Scripta Mater., 47 (2002): 669-675.

DOI: 10.1016/s1359-6462(02)00266-x

[7] Chen QZ, Jones N, Knowles DM. The microstructures of base/modified RR2072 SX superalloys and their effects on creep properties at elevated temperatures. Acta Mater 50 (2002): 1095-1112.

DOI: 10.1016/s1359-6454(01)00410-4

[8] Evans ND, Maziasz PJ, Swindemen RW, Smith GD. Microstructure and phase stability in INCONEL alloy 740 during creep . Scripta Mater., 51 (2004): 503-507.

DOI: 10.1016/j.scriptamat.2004.05.047

[9] Liu LR, Jin T, Zhao NR, et al. Formation of carbides and their effects on stress rupture of a Ni-base single crystal superalloy. Mater. Sci. Eng. A, 361(2003): 191-197.

DOI: 10.1016/s0921-5093(03)00517-3

[10] Yi JZ, Torbet CJ, Feng Q, et al. Ultrasonic fatigue of a single crystal Ni-base superalloy at 1000 °C. Mater. Sci. Eng. A. 443(2007): 142-149.

DOI: 10.1016/j.msea.2006.08.028

[11] Reed RC. The superalloys: fundamentals and applications. First ed. Cambridge: Cambridge University Press; (2006).