Effect of Al Content on Microstructure and Creep Behavior of Low Density Ni₃Al-Base Single Crystal Superalloy

Abstract:

The influence of Al content on microstructure and creep behavior of Ni₃Al-Base single crystal superalloy was investigated. Two Ni₃Al-Base single crystal alloys with different Al contents were prepared in a vacuum induction furnace by screw selection crystal method.Optical microscope (OM), differential scanning calorimetry (DSC),scanning electron microscope (SEM),energy dispersive spectrometer (EDS),and X-ray diffraction (XRD) were used to observe the microstructure of the alloys.The experimental results showed thatthe volume fraction, mean size of the eutectic phase γ-γ′, γ′before and after heat treatment display differences with the Al content. It has been found that the stress-rupture lives increased with theAl content.The reasons may be as follows.Firstly, as content of Al increases, the reinforcing phaseγ′increases, resulting in the improvement of the precipitation strengthening.And secondly, the increasing of Al content leadsthe decreasing lattice mismatch of γ/γ′ phase, which enhances the coherent strain field around theγ′ phase and the hence increase the strengthening effect to the alloy.

• Periodical: Materials Science Forum (Volume 816)
• Pages: 297-303
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.816.297
• Online since: April 2015
• Authors: Hao Fu*, Shu Suo Li, Yan Ling Pei, Sheng Kai Gong
• Keywords: Al, Heat Treatment, Microstructure, Ni₃Al-based Single Crystal Alloys, Stress-Rupture Property

References

[1] Duhl, M. Gel& DN, and A. F. Giamei. The development of single crystal superalloy turbine blades., Superalloys 1980 (1980).

DOI: 10.7449/1980/superalloys_1980_205_214

[2] Leverant, G. R., B. H. Kear, and J. M. Oblak. Creep of precipitation-hardened nickel-base alloy single crystals at high temperatures., Metallurgical Transactions 4. 1 (1973): 355-362.

DOI: 10.1007/bf02649637

[3] Reed, R. C., D. C. Cox, and C. M. F. Rae. Damage accumulation during creep deformation of a single crystal superalloy at 1150 C., Materials Science and Engineering: A 448. 1 (2007): 88-96.

DOI: 10.1016/j.msea.2006.11.101

[4] Mirkin, I. L., and O. D. Kancheev. Relationship between heat resistance and difference in lattice spacings of phases in precipitation-hardening alloys., Metal Science and Heat Treatment 9. 1 (1967): 10-13.

DOI: 10.1007/bf00657546

[5] Feller-Kniepmeier M, Link T. Correlation of microstructure and creep stages in the< 100>oriented superalloy SRR 99 at 1253K,. Metallurgical Transactions: A 20. 1(1989): 1233-1238.

DOI: 10.1007/bf02647405

[6] Yu, X. H., et al. Design of quaternary Ir-Nb-Ni-Al refractory superalloys., Metallurgical and materials transactions A 31. 1 (2000): 173-178.

DOI: 10.1007/s11661-000-0063-9

[7] Shui, Li, et al. Influence of pre-compression on microstructure and creep characteristic of a single crystal nickel-base superalloy., Materials Science and Engineering: A 418. 1 (2006): 229-235.

DOI: 10.1016/j.msea.2005.11.028

[8] Drew, G. L., et al. Single crystal superalloys; the transition from primary to secondary creep., Superalloys 2004 (2004).

DOI: 10.7449/2004/superalloys_2004_127_136

[9] Nystrom J.D., Pollck T.M., Murphy W.H., and Garg A. Discontinuous cellular precipitation in a high-refractory nickel-based superalloy., Metall Mater Trans: A28(1997): 2443.

DOI: 10.1007/s11661-997-0001-1

[10] Nabarro, Frank Reginald Nunes, and F. De Villiers. Physics of creep and creep-resistant alloys. CRC press, (1995).

[11] McLean, Malcolm. Directionally solidified materials for high temperature service., (1988).

[12] Kamaraj, M. Rafting in single crystal nickel-base superalloys—An overview., Sadhana 28. 1-2 (2003): 115-128.

DOI: 10.1007/bf02717129

[13] Kostka, A., et al. L12-phase cutting during high temperature and low stress creep of a Re-containing Ni-base single crystal superalloy., Journal of materials science 42. 11 (2007): 3951-3957.

DOI: 10.1007/s10853-006-0166-9

[14] Carry, C., and J. L. Strudel. Apparent and effective creep parameters in single crystals of a nickel base superalloy—I Incubation period., ActaMetallurgica 25. 7 (1977): 767-777.

DOI: 10.1016/0001-6160(77)90092-x

[15] Wilson, B. C., J. A. Hickman, and G. E. Fuchs. The effect of solution heat treatment on a single-crystal Ni-based superalloy., JOM 55. 3 (2003): 35-40.

DOI: 10.1007/s11837-003-0158-z

[16] Pollock, T. M., and R. D. Field. Dislocations and high-temperature plastic deformation of superalloy single crystals., Dislocations in solids 11 (2002): 547-618.

DOI: 10.1016/s1572-4859(02)80014-6

[17] Carroll, L. J., et al. High refractory, low misfit Ru-containing single-crystal superalloys., Metallurgical and Materials Transactions A 37. 10 (2006): 2927-2938.

DOI: 10.1007/s11661-006-0174-z

[18] Gabb, T. P., et al. The role of interfacial dislocation networks in high temperature creep of superalloys., Materials Science and Engineering: A 118 (1989): 59-69.

DOI: 10.1016/0921-5093(89)90058-0

[19] Zhang, J. X., et al. Interfacial dislocation networks strengthening a fourth-generation single-crystal TMS-138 superalloy., Metallurgical and Materials Transactions A 33. 12 (2002): 3741-3746.

DOI: 10.1007/s11661-002-0246-7

[20] Nathal, M. V., R. A. MacKay, and R. V. Miner. Influence of precipitate morphology on intermediate temperature creep properties of a nickel-base superalloy single crystal., Metallurgical Transactions A 20. 1 (1989): 133-141.

DOI: 10.1007/bf02647500