Microstructure Evolution and Strain Features of a Single Crystal Nickel Base Superalloy during Tensile/Compression Creep

Abstract:

By means of tensile and compression creep testing and SEM, TEM observation, an investigation has been made into the microstructure evolution of a single crystal nickel base superalloy during tensile / compression creep. Results show that the cubic γ′ phase in the superalloy is transformed into the N-type meshlike structure along the direction vertical to stress axis during tensile creep. The cubic γ′ phase is transformed into the P-type structure along the direction parallel to stress axis during compression creep. An obvious asymmetry strain of the alloy occurs during tensile and compression creep, the formation of the needle-like γ′ rafts during compression creep is a main reason of the alloy displaying a smaller strain. During compressive creep, the deformation feature of the alloy is the <110> and (1/3) <112> super dislocations shearing into the γ′ rafts. The deformation mechanism of the alloy, in the stage state of tensile creep, is dislocation climb over the γ′ rafts.

• Periodical: Materials Science Forum (Volumes 546-549)
• Pages: 1225-1228
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.546-549.1225
• Online since: May 2007
• Authors: Fan Lai Meng, Su Gui Tian, Ming Gang Wang, Xing Fu Yu, Hong Qiang Du, Li Shui, Ling Wang
• Keywords: Compression Creep, Micro-Structure Evolution, Single Crystal Nickel-Base Superalloy, Tensile Creep

References

[1] J.K. Tien and S.M. Copley: Metal. Trans. 2, (1971), p.215.

[2] M.I. Nathal and L.J. Ebert: Scr. Metal. Vol. 17 (1983), p.1151.

[3] P. Caron, P.J. Henderson, T. K han, M. McLean, Scripta Metall. Vol. 20 (1986), p.875.

[4] T. M. Pollock and A.S. Argon: Acta Metal. Mater. Vol. 42 (1994), p.1859.

[5] G.L. Drew, R.C. Reed, K. Kakehi, C.M.F. Rae, Superalloys (2004).