Effects of Cooling Rates after Solution Heat Treatment on the Creep Behavior of Directionally Solidified CM-247LC Superalloy

Abstract:

In this study, three cooling rates, namely, Argon cooling, air cooling and furnace cooling after solution heat treatment of directionally solidified CM-247LC superalloy were proposed to explore the high temperature/low stress (982°C/200MPa) creep behavior. Standard heat treatment schemes of DS CM-247LC superalloy are solution treatment at 1260°C for 2 hour, then first aging at 1079°C for 4 hour and followed by second aging at 871°C for 20 hour. Results show that Argon cooling specimen provided the longest creep rupture life, which exceeds that of the air cooling specimen around 40 hour; whereas the creep rupture life of furnace cooling specimen was the shortest one of 100 hour, which is shorter than that of the air cooling specimen around 40 hour. Rupture strains of all three specimens were almost identical around 20%. Microstructural differences of gamma prime morphology were observed to explain the differences of creep rupture life.

• Periodical: Materials Science Forum (Volume 788)
• Pages: 549-553
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.788.549
• Online since: April 2014
• Authors: Mau Sheng Chiou, An Chou Yeh, Sheng Rui Jian*, Chen Ming Kuo
• Keywords: High-Temperature Creep, Ni Based Superalloy

References

[1] A.C. Yeh, K. Kawagishi, H. Harada, T. Yokokawa, Y. Koizumi, T. Kobayashi, D.H. Ping, J. Fujioka, and T. Suzuki, Development of Si-bearing 4th generation Ni-base single crystal superalloys, Superalloys2008. 14-18 (2008) 619-628.

DOI: 10.7449/2008/superalloys_2008_619_628

[2] S. Ma, D. Brown, M.A.M. Bourke, M.R. Daymond, and B.S. Majumdar, Microstrain evolution during creep of a high volume fraction superalloy, Materials Science and Engineering A. 399 (2005) 141-153.

DOI: 10.1016/j.msea.2005.02.034

[3] C.M. Kuo, Y.T. Yang, H.Y. Bor, C.N. Wei, and C.C. Tai, Aging effects on the microstructure and creep behavior of Inconel 718 superalloy, Materials Science and Engineering A. 510 (2009) 289-294.

DOI: 10.1016/j.msea.2008.04.097

[4] M. Brunner, M. Bensch, R. Vӧlkl, E. Affeldt, and U. Glatzel, Thickness influence on creep properties for Ni-based superalloy M247LC SX, Materials Science and Engineering A. 550 (2012) 254-262.

DOI: 10.1016/j.msea.2012.04.067

[5] H.E. Huand, and C.H. Koo, Characteristics and mechanical properties of polycrystalline CM 247 LC superalloy casting, Materials Transactions. 2 (2004) 562-568.

DOI: 10.2320/matertrans.45.562

[6] A.C. Yeh, K.W. Lu, C.M. Kuo, H.Y. Bor, and C.N. Wei, Effect of serrated grain boundaries on the creep property of Inconel 718 superalloy, Materials Science and Engineering A. 530 (2011) 525-529.

DOI: 10.1016/j.msea.2011.10.014

[7] J.S. Van Sluytman, and T.M. Pollock, Optimal precipitate shapes in nickel-base γ-γ' alloys, Acta Materialia. 60 (2012) 1771-1783.

DOI: 10.1016/j.actamat.2011.12.008

[8] N. Bozzolo, N. Souaï, and R.E. Logé, Evolution of microstructure and twin density during thermomechanical processing in a γ-γ' nickel-based superalloy, Acta Materialia. 60 (2012) 5056-5066.

DOI: 10.1016/j.actamat.2012.06.028

[9] J.J. Moverare, S. Johansson, and R.C. Reed, Deformation and damage mechanisms during thermal-mechanical fatigue of a single-crytal superalloy, Acta Materialia. 57 (2009) 2266-2276.

DOI: 10.1016/j.actamat.2009.01.027

[10] J. Tiley, G.B. Viswanathan, J.Y. Hwang, A. Shiveley, and R. Banerjee, Evaluation of gamma prime volume fractions and lattice misfits in a nickel base superally using the external standard X-ray diffraction method, Materials Science and Engineering A. 528 (2010) 32-36.

DOI: 10.1016/j.msea.2010.07.036

[11] R.R. Unocic, N. Zhou, L. Kovarik, C. Shen, Y. Wang, and M.J. Mills, Dislocation decorrelation and relationship to deformation microtwins during creep of a γ' precipitate strengthened Ni-based superalloy, Acta Materialia. 59 (2011) 7325-7339.

DOI: 10.1016/j.actamat.2011.07.069

[12] N.E. Bagoury, and A. Nofal, Microstructure of an experimental Ni base superalloy under various casting conditions, Materials Science and Engineering A. 527 (2010) 7793-7800.

DOI: 10.1016/j.msea.2010.08.050

[13] G.M. Han, J.J. Yu, X.F. Sun, and Z.Q. Hu, Thermo-mechanical fatigue behavior of a single crystal nickel-based superalloy, Materials Science and Engineering A. 528 (2011) 6217-6224.

DOI: 10.1016/j.msea.2011.04.083

[14] T.M. Pollock, and S. Tin, Nickel-based superalloys for advanceced turbine engines: chemistry, microstructure, and properties, Journal of Propulsion and Power. 22 (2006) 361-374.

DOI: 10.2514/1.18239

[15] I.S. Kim, B.G. Choi, S.M. Seo, D.H. Kim, and C.Y. Jo, Influence of heat treatment on microstructure and tensile properties of conventionally cast and directionally solidified superalloy CM247LC, Materials Letters. 62 (2008) 1110-1113.

DOI: 10.1016/j.matlet.2007.07.058

[16] M.Z. Alam, D.V.V. Satyanarayana, D. Chatterjee, R. Sarkar, and D.K. Das, Effect of prior cyclic oxidation on the creep behavior of directionally solidified (DS) CM-247LC alloy, Materials Science and Engineering A. 536 (2012) 14-23.

DOI: 10.1016/j.msea.2011.10.016

[17] J. Coakley, and D. Dye, Lattice strain evolution in a high volume fraction polycrystal nickel superalloy, Scripta Materialia. 67 (2012) 435-438.

DOI: 10.1016/j.scriptamat.2012.05.015

[18] D. Leidermark, J.J. Moverare, S. Johansson, K. Simonsson, and S. Sjӧstrӧm, Tension/compression asymmetry of a single-crystal superalloy in virgin and degraded condition, Acta Materialia. 58 (2010), pp.4986-4997.

DOI: 10.1016/j.actamat.2010.05.032

[19] M.Hantcherli, F.P. Sturmel, B. Viguier, J. Douin, and A. Coujou, Evolution of interfacial dislocation network during anisothermal high-temperature creep of a nickel-based superalloy, Scripta Materialia. 66 (2012) 143-146.

DOI: 10.1016/j.scriptamat.2011.10.022

[20] ASTM E 139-06: Annual Book of ASTM Standards Vol. 3.01, (2006), pp.319-331.