Electrical Characterization of Aged Waspaloy Microstructures


Article Preview

Non-destructive evaluation (NDE) techniques offer the potential advantage of achieving fast throughput microstructural characterization as well as monitoring that could be extremely valuable in assessing the mechanical integrity of turbine engine components. It is well known that the γ′ precipitate size and distribution can often determine the mechanical strength of nickel base alloys. In this investigation, Waspaloy, an age-hardening superalloy, was chosen as the candidate to produce varied microstructures, which were subsequently characterized via the DC four-probe resistivity method. Specimens with average grain sizes of 13, 52 and 89 μm were obtained upon solutionizing at 1045°C, 1090°C and 1145°C respectively. The specimens were annealed at 1045°C to stabilize the vacancy concentration prior to aging at 800°C for times ranging from 0.1 to 100 hours. Sub-grain microstructures examined in the SEM showed progressive growth of γ′ precipitates with increased aging duration in all cases. The measurements of DC four-probe resistivity showed a consistent drop in the resistivity with increased aging time, which was concurrent with the growth of the precipitates.



Advanced Materials Research (Volumes 15-17)

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer and C. Ravindran




V.S. Kumar et al., "Electrical Characterization of Aged Waspaloy Microstructures", Advanced Materials Research, Vols. 15-17, pp. 876-881, 2007

Online since:

February 2006




[1] D.Q. Wang, S.S. Babu, E.A. Payzant, P.G. Radaelli and A.C. Hannon: Metall. and Mater. Trans. Vol. 32A (2001), p.1551.

[2] P.R. Jemian, R.A. Gerhardt and G.G. Long: in press.

[3] A.I. Lavrentyev and W.A. Veronesi: Rev. of Quant. Non-destr. Eval. Vol. 21 (2002), p.1659.

[4] P. Haldipur, F.J. Margetan and R.B. Thompson: Rev. of Quant. Non-destr. Eval. Vol. 22 (2003), p.1355.

[5] J. Kang, J. Qu, A. Saxena and L. Jacobs: Rev. of Quant. Non-destr. Eval. Vol. 23 (2004), p.1248.

[6] R. Ferragut, A. Somoza and L. Torriaini: Mater. Sci. and Eng. Vol. A334 (2002), p.1.

[7] C. Panseri and T. Federighi: Acta Metall. Vol. 8 (1959), p.217.

[8] F. Yu and B. Nagy: Jrnl. of App. Phys. Vol. 95(12) (2004), p.1.

[9] F. Yu and B. Nagy: Jrnl. of App. Phys. Vol. 96(2) (2004), p.1.

[10] X. Zou, T. Makram and R.A. Gerhardt: Mater. Res. Symp. Proc. Vol. 699 (2002), p.301.

[11] V. Siva Kumar G. Kelekanjeri and R.A. Gerhardt: Electrochim. Acta. Vol. 51(8-9) (2006) p.1873.

[12] K. Pinkos, C. Laboy and R.A. Gerhardt: Mater. Res. Symp. Proc. Vol. 699 (2002), p.289.

[13] H. Topsoe: GeometricFactors in Four Point Resistivity Measurement Bulletin 472-13 (1968).

[14] H. Kimura and R. Maddin: Quench Hardening in Metals (North-Holland Pubslishing Company, Amsterdam 1971).

[15] H.T. Kim, S.S. Chun, X.X. Yao, Y. Fang, J. Choi: Jrnl. of Mater. Sci. Vol. 32 (1997), p.4917.