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Manuscript submitted November 13, 2017.
Correlative high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy are used to study deformation-induced planar faults in the single-crystal superalloy MD2 crept at 800 °C and 650 MPa. Segregation of Cr and Co at microtwins, anti-phase boundaries (APB), and complex/superlattice extrinsic and intrinsic stacking faults (CESF/SESF and CISF/SISF) is confirmed and quantified. The extent of this is found to depend upon the fault type, being most pronounced for the APB. The CESF/SESF is studied in detail due to its role as a precursor of the microtwins causing the majority of plasticity under these conditions. Quantitative modeling is carried out to rationalize the findings; the experimental results are consistent with a greater predicted velocity for the lengthening of the CESF/SESF—compared with the other types of fault—and hence confirm its role in the diffusion-assisted plasticity needed for the microtwinning mechanism to be operative.
R. J. McCabe, I. J. Beyerlein, J. S. Carpenter, and N. A. Mara. The critical role of grain orientation and applied stress in nanoscale twinning. Nat. Commun,, 5(May):3806, 2014. CrossRef
T. M. Smith, B. D. Esser, N. Antolin, A. Carlsson, R. E. A. Williams, A. Wessman, T. Hanlon, H. L. Fraser, W. Windl, D. W. McComb, and M. J. Mills. Phase transformation strengthening of high-temperature superalloys. Nat. Commun., 7:13434, 2016. CrossRef
H. Van Swygenhoven, P. M. Derlet, and A. G. Froseth. Stacking fault energies and slip in nanocrystalline metals. Nat. Mater., 3(6):399–403, 2004. CrossRef
Q. Qin and J. L. Bassani. Non-associated plastic flow in single crystals. J. Mech. Phys. Solids, 40(4):835–862, 1992. CrossRef
Q. Qin and J. L. Bassani. Non-schmid yield behavior in single crystals. J. Mech. Phys. Solids, 40(4):813–833, 1992. CrossRef
N. Tsuno, S. Shimabayashi, K. Kakehi, C. M. F. Rae, and R. C. Reed. Tension/compression asymmetry in yield and creep strengths of Ni based superalloys. Superalloys 2008, pages 433–442, 2008.
S. Keshavarz, A. C. E. Ghosh, S.and Reid, and S. A. Langer. A non-Schmid crystal plasticity finite element approach to multi-scale modeling of nickel-based superalloys. Acta Mater., 114:106–115, 2016. CrossRef
D. Leidermark, J. J. Moverare, S. Johansson, K. Simonsson, and S. Sjöström. Tension/compression asymmetry of a single-crystal superalloy in virgin and degraded condition. Acta Mater., 58:4986–4997, 2010. CrossRef
R.C. Reed. The Superalloys: Fundamentals and Applications. Cambridge, 2006.
I. Alvarez, A. C. Picasso, and A. J. Marzocca. Cross-slip and dislocation climb in nickel-base superalloys. Mater. Sci. Eng. A, 236:7–10, 1997.
D. J. Crudden, A. Mottura, N. Warnken, B. Raeisinia, and R. C. Reed. Modelling of the influence of alloy composition on flow stress in high-strength nickel-based superalloys. Acta Mater., 75:356–370, 2014. CrossRef
A. Vattré, B. Devincre, and A. Roos. Orientation dependence of plastic deformation in nickel-based single crystal superalloys: discrete-continuous model simulations. Acta Materialia, 58(6):1938–1951, 2010. CrossRef
M. Kolbe. The high temperature decrease of the critical resolved shear stress in nickel-base superalloys. Prog. Mater. Sci., A319-321:383–387, 2001.
D. Barba, D. Pedrazzini, A. Collins, A. J. Wilkinson, M. P. Moody, P. A. J. Bagot, A. Jérusalem, and R. C. Reed. On the microtwinning mechanism in a single crystal superalloy. Acta Mater., 127:37–40, 2017.
D. Barba, S. Pedrazzini, A. Vilalta-Clemente, A. J. Wilkinson, M. P. Moody, P. A. J. Bagot, A. Jérusalem, and R. C. Reed. On the composition of microtwins in a single crystal nickel-based superalloy. Scripta Mater., 127:37–40, 2017. CrossRef
D. M. Knowles and S. Gunturi. The role of \(\langle 112\rangle \) 111 slip in the asymmetric nature of creep of single crystal superalloy CMSX-4. Mater. Sci. Eng. A, 328:223–237, 2002. CrossRef
T. M. Smith, R. R. Unocic, H. Deutchman, and M. J. Mills. Creep deformation mechanism mapping in nickel base disk superalloys. Mater. High Temp., 33(33):1–12, 2016.
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 Mater., 59(19):7325–7339, 2011. CrossRef
H. Hoeft and P. Schwaab. Investigations towards optimizing EDS analysis by the Cliff–Lorimer method in scanning transmission electron microscopy. X-Ray Spectrometry, 17(5):201–208, 1988. CrossRef
K. Kakehi. Influence of secondary precipitates and crystallographic orientation on the strength of single crystals of a ni-based superalloy. Metall. Mater. Trans. A, 30A(5):1249–1259, 1999. CrossRef
K. Kakehi. Tension/compression asymmetry in creep behavior of a ni-based superalloy. Scripta Mater., 41(5), 461-465 1999. CrossRef
M. Yamashita and K. Kakehi. Tension/compression asymmetry in yield and creep strengths of ni-based superalloy with a high amount of tantalum. Scripta Mater., 55(2):139–142, 2006. CrossRef
L. P. Freund, O. M. Messé, J. S. Barnard, M. Göken, S. Neumeier, and C. M. Rae. Segregation assisted microtwinning during creep of a polycrystalline L12-hardened Co-base superalloy. Acta Mater., 123:295–304, 2017. CrossRef
T. M. Smith, B. D. Esser, N. Antolin, G. B. Viswanathan, T. Hanlon, A. Wessman, D. Mourer, W. Windl, D. W. McComb, and M. J. Mills. Segregation and \(\eta \) phase formation along stacking faults during creep at intermediate temperatures in a Ni-based superalloy. Acta Mater., 100:19–31, 2015. CrossRef
T.M. Smith Jr.: Orientation and Alloying Effects on Creep Strength in Ni-Based Superalloys. Ph.D. thesis, The Ohio State University, 2016.
A. Breidi, J. Allen, and A. Mottura. First-principles modeling of superlattice intrinsic stacking fault energies in Ni 3 Al based alloys. Acta Mater., 145:97–108, 2018. CrossRef
M. S. Titus, A. Mottura, G. B. Viswanathan, A. Suzuki, M. J. Mills, and T. M. Pollock. High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys. Acta Mater., 89:423–437, 2015. CrossRef
L. Kovarik, R. R. Unocic, J. Li, P. Sarosi, C. Shen, Y. Wang, and M. J. Mills. Microtwinning and other shearing mechanisms at intermediate temperatures in Ni-based superalloys. Prog. Mater. Sci., 54:839–873, 2009. CrossRef
D. Caillard and J. Martin: Thermally Activated Mechanisms in Crystal Plasticity. Pergamon Materials Series, vol. 8, Pergamon, Oxford, 2003.
T. Smith, Y. Rao, Y. Wang, M. Ghazisaeidi, and M. Mills. Diffusion processes during creep at intermediate temperatures in a Ni-based superalloy. Acta Mater., 141:261–272, 2017. CrossRef
J. O. Andersson, T. Helander, L. Höglund, P. Shi, and B. Sundman. Thermo-Calc & DICTRA, computational tools for materials science. Calphad, 26(2):273–312, 2002. CrossRef
Thermotech Ni-based Superalloys Database v8.0, Accessed January 2015.
V. A. Vorontsov, R. E. Voskoboinikov, and C. M. F. Rae. Shearing of γ′ precipitates in Ni-base superalloys: a phase field study incorporating the effective γ-surface. Philos. Mag., 92(5):608–634, 2012. CrossRef
E. I. Galindo-Nava, L. D. Connor, and C. M. F. Rae. On the prediction of the yield stress of unimodal and multimodal γ′ Nickel-base superalloys. Acta Mater., 98:377–390, 2015. CrossRef
A. Ma, D. Dye, and R. C. Reed. A model for the creep deformation behaviour of single-crystal superalloy CMSX-4. Acta Mater., 56(8):1657–1670, 2008. CrossRef
R. C. Reed and C. M. F. Rae: 22—Physical Metallurgy of the Nickel-Based Superalloys. In D. E. Laughlin and K. Hono, editors, Physical Metallurgy, pages 2215–2290. Elsevier, Oxford, 2014. CrossRef
Z. Zhu, H. Basoalto, N. Warnken, and R. C. Reed. A model for the creep deformation behaviour of nickel-based single crystal superalloys. Acta Mater., 60(12):4888–4900, 2012. CrossRef
A. Sengupta, S. K. Putatunda, L. Bartosiewicz, J. Hangas, P. J. Nailos, M. Peputapeck, and F. E. Alberts. Tensile behavior of a new single-crystal nickel-based superalloy (CMSX-4) at room and elevated temperatures. J. Mater. Eng. Perform., 3(1):73–81, 1994. CrossRef
A. Fick. On liquid diffusion. The London, Edinburgh,and Dublin Philosophical Magazine and Journal of Science-, 10:30–39, 1855. CrossRef
G. J. Jones and R. K. Trivedi. Lateral growth in solid–solid phase transformations. J. Appl. Phys., 42(11):4299–4304, 1971. CrossRef
C. Atkinson. The growth kinetics of individual ledges during solid/solid phase transformations. Proc. R. Soc. Lond., 378: 351–368, 1981. CrossRef
- Segregation-Assisted Plasticity in Ni-Based Superalloys
T. M. Smith
M. J. Mills
R. C. Reed
- Springer US
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