Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-28T09:52:20.966Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructure evolution in L12 hardened Co-base superalloys during creep

Published online by Cambridge University Press:  18 September 2017

Yuzhi Li ,
Florian Pyczak ,
Jonathan Paul ,
Michael Oehring ,
Uwe Lorenz  and
Zekun Yao
Yuzhi Li
Affiliation:
School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China
Florian Pyczak*
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany
Jonathan Paul
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany
Michael Oehring
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany
Uwe Lorenz
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht 21502, Germany
Zekun Yao
Affiliation:
School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

The plastic deformation mechanisms and the microstructure development during creep deformation of L12-hardened Co-base superalloys show a number of unique features. The preferred orientation of rafting is determined by their positive lattice mismatch. In addition, the regular interfacial dislocation networks often found in rafted specimens of other types of superalloys do not form. While the ordered γ′-L12 precipitates are supposed to harden the material, they are actually found to be frequently cut by partial dislocations generating stacking faults. In this work, specimens from creep tests interrupted at different strains were investigated using transmission and scanning electron microscopy. By this, it is possible to find out which of these processes take place in which stage of creep deformation. For a better understanding of creep deformation, the balance between γ′ cutting and dislocation activity within the matrix channels is of special interest.

Keywords

Codislocationmicrostructure
Type
Articles
Information
Journal of Materials Research , Volume 32 , Issue 24: Focus Issue: Mechanical Properties and Microstructure of Advanced Metallic Alloys—in Honor of Prof. Haël Mughrabi PART B , 28 December 2017 , pp. 4522 - 4530
Check for updates
Copyright
Copyright © Materials Research Society 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Contributing Editor: Mathias Göken

References

REFERENCES

Sato, J., Omori, T., Oikawa, K., Ohnuma, I., Kainuma, R., and Ishida, K.: Cobalt-base high-temperature alloys. Science 312, 90 (2006).CrossRefGoogle ScholarPubMed
Bauer, A., Neumeier, S., Pyczak, F., and Göken, M.: Microstructure and creep strength of different γ/γ′-strengthened Co-base superalloy variants. Scr. Mater. 63, 1197 (2010).Google Scholar
Pollock, T.M., Dibbern, J., Tsunekane, M., Zhu, J., and Suzuki, A.: New Co-based γ–γ′ high temperature alloys. JOM 62, 58 (2010).Google Scholar
Suzuki, A., DeNolf, G.C., and Pollock, T.M.: Flow stress anomalies in γ/γ′ two-phase Co–Al–W-base alloys. Scr. Mater. 56, 385 (2007).Google Scholar
Suzuki, A. and Pollock, T.M.: High-temperature strength and deformation of γ/γ′ two-phase Co–Al–W-base alloys. Acta Mater. 56, 1288 (2008).Google Scholar
Bauer, A., Neumeier, S., Pyczak, F., Singer, R.F., and Göken, M.: Creep properties of different γ′-strengthened Co-base superalloys. Mater. Sci. Eng., A 550, 333 (2012).Google Scholar
Bauer, A., Neumeier, S., Pyczak, F., and Göken, M.: Creep strength and microstrcuture of polycrystalline γ′-strengthened cobalt-base superalloys. In Superalloys 2012, Huron, E.S., Reed, R.C., Hardy, M.C., Mills, M.J., Montero, R.E., Portella, P.D., and Telesman, J., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 2012); p. 695.Google Scholar
Mughrabi, H.: The importance of sign and magnitude of γ/γ′ lattice misfit in superalloys—with special reference to the new γ′-hardened cobalt-base superalloys. Acta Mater. 81, 21 (2014).Google Scholar
Nabarro, F.R.N.: Rafting in superalloys. Metall. Trans. A 27, 513 (1996).Google Scholar
Mughrabi, H. and Tetzlaff, U.: Microstructure and high-temperature strength of monocrystalline nickel-base superalloys. Adv. Eng. Mater. 2, 319 (2000).3.0.CO;2-S>CrossRefGoogle Scholar
Pollock, T.M. and Argon, A.S.: Directional coarsening in nickel-base single crystals with high volume fractions of coherent precipitates. Acta Metall. Mater. 42, 1859 (1994).Google Scholar
Pollock, T.M. and Argon, A.S.: Creep resistance of CMSX-3 nickel base superalloy single crystals. Acta Metall. Mater. 40, 1 (1992).Google Scholar
Link, T. and Feller-Kniepmeier, M.: Shear mechanisms of the γ′ phase in single-crystal superalloys and their relation to creep. Metall. Trans. A 23, 99 (1992).Google Scholar
Pyczak, F., Bauer, A., Göken, M., Neumeier, S., Lorenz, U., Oehring, M., Schell, N., Schreyer, A., Stark, A., and Symanzik, F.: Plastic deformation mechanisms in a crept L12 hardened Co-base superalloy. Mater. Sci. Eng., A 571, 13 (2013).Google Scholar
Titus, M.S., Eggeler, Y.M., Suzuki, A., and Pollock, T.M.: Creep-induced planar defects in L12-containing Co- and CoNi-base single-crystal superalloys. Acta Mater. 82, 530 (2015).Google Scholar
Titus, M.S., Mottura, A., Viswanathan, G.B., Suzuki, A., Mills, M.J., and Pollock, T.M.: High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys. Acta Mater. 89, 423 (2015).Google Scholar
Eggeler, Y.M., Müller, J., Titus, M.S., Suzuki, A., Pollock, T.M., and Spiecker, E.: Planar defect formation in the γ′ phase during high temperature creep in single crystal CoNi-base superalloys. Acta Mater. 113, 335 (2016).Google Scholar
Shi, L., Yu, J.J., Cui, C.Y., and Sun, X.F.: Microstructural stability and tensile properties of a Ti-containing single-crystal Co–Ni–Al–W-base alloy. Mater. Sci. Eng., A 646, 45 (2015).Google Scholar
Mughrabi, H.: γ/γ′ rafting and its effect on the creep and fatigue behaviour of monocrystalline superalloys. In The Johannes Weertmann Symposium, Arsenault, R.J., Cole, D., Gross, T., Kostorz, G., Liaw, P.K., Parameswaran, S., and Sizek, H., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 1996); p. 267.Google Scholar
Hammer, J. and Mughrabi, H.: High temperature creep and microstructure of the monocrystaline nickel-base superalloys SRR 99. In EUROMAT 89, Exner, H.E. and Schuhmacher, V., eds. (Proceedings of the First European Conference on Advanced Materials and Processes, DGM Informationsgesellschaft Verlag, Oberursel 1990); p. 445.Google Scholar
Pyczak, F., Bauer, A., Göken, M., Lorenz, U., Neumeier, S., Oehring, M., Paul, J., Schell, N., Schreyer, A., Stark, A., and Symanzik, F.: The effect of tungsten content on the properties of L12-hardened Co–Al–W alloys. J. Alloys Compd. 632, 110 (2015).Google Scholar
Zhou, H.J., Chang, H., and Feng, Q.: Transient minimum creep of a γ′ strengthened Co-base single-crystal superalloy at 900 °C. Scr. Mater. 135, 84 (2017).Google Scholar
Field, R.D., Pollockf, T.M., and Murphy, W.H.: The development of γ/γ′ interfacial dislocation networks during creep in Ni-base superalloys. In Superalloys 1992, Antolovich, S.D., Stusrud, R.W., MacKay, R.A., Anton, D.L., Khan, T., Kissinger, R.D., and Klarstrom, D.L., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 1992); p. 557.Google Scholar
Tanaka, K., Ooshima, M., Tsuno, N., Sato, A., and Inui, H.: Creep deformation of single crystals of new Co–Al–W-based alloys with fcc/L12 two-phase microstructures. Philos. Mag. 92, 4011 (2012).Google Scholar
Yan, H-Y., Vorontsov, V.A., Coakley, J., Jones, N.G., Stone, H.J., and Dye, D.: Quaternary alloying effects and the prospects for a new generation of Co-base superalloys. In Superalloys 2012, Huron, E.S., Reed, R.C., Hardy, M.C., Mills, M.J., Montero, R.E., Portella, P.D., and Telesman, J., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 2012); p. 705.Google Scholar
Feller-Kniepmeier, M. and Link, T.: Dislocation structures in γ–γ′ interfaces of the single-crystal superalloy SRR 99 after annealing and high temperature creep. Mater. Sci. Eng., A 113, 191 (1989).CrossRefGoogle Scholar
Pyczak, F., Devrient, B., and Mughrabi, H.: The effects of different alloying elements on the thermal expansion coefficients, lattice constants and misfit of nickei-based superalloys investigated by X-ray diffraction. In Superalloys 2004, Green, K.A., Pollock, T.M., Harada, H., Howson, T.E., Reed, R.C., Schirra, J.J., and Walston, S., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 2004); p. 827.Google Scholar
Tanaka, K., Ohashi, T., Kishida, K., and Inui, H.: Single-crystal elastic constants of Co3(Al,W) with the L12 structure. Appl. Phys. Lett. 91, 181907 (2007).Google Scholar
Okamoto, N.L., Oohashi, T., Adachi, H., Kishida, K., Inui, H., and Veyssière, P.: Plastic deformation of polycrystals of Co3(Al,W) with the L12 structure. Philos. Mag. 91, 3667 (2011).Google Scholar
Kraft, S., Altenberger, I., and Mughrabi, H.: Directional γ–γ′ coarsening in a monocrystalline nickel-base superalloy during low-cycle thermomechanical fatigue. Scr. Metall. Mater. 32, 411 (1995).CrossRefGoogle Scholar
Fährmann, M., Fährmann, E., Paris, O., Fratzl, P., and Pollock, T.M.: An experimental study of the role of plasticity in the rafting kinetics of a single crystal Ni-base superalloy. In Superalloys 1996, Kissinger, R.D., Deye, D.J., Anton, D.L., Cetel, A.D., Nathal, M.V. and Woodford, D.A., eds. (The Minerals, Metals & Materials Society, Warrendale, PA, 1996); p. 191.Google Scholar
Pineau, A.: Influence of uniaxial stress on the morphology of coherent precipitates during coarsening–elastic considerations. Acta Metall. 24, 559 (1976).CrossRefGoogle Scholar
Kobayashi, S., Tsukamoto, Y., Takasugi, T., Chinen, H., Omori, T., Ishida, K., and Zaefferer, S.: Determination of phase equilibria in the Co-rich Co–Al–W ternary system with a diffusion-couple technique. Intermetallics 17, 1085 (2009).Google Scholar
Saal, J.E. and Wolverton, C.: Thermodynamic stability of Co–Al–W L12 γ′. Acta Mater. 61, 2330 (2013).Google Scholar
Lass, E.A., Williams, M.E., Campbell, C.E., Moon, K-W., and Kattner, U.R.: γ′ phase stability and phase equilibrium in ternary Co–Al–W at 900 °C. J. Phase Equilib. Diffus. 35, 711 (2014).Google Scholar