density of y’,, calculated from the AFM images might be overestimated. The quantitative analysis Comp
by AFM was already reported to be an alternative method for measuring a particle size distribution (nam
and volume fraction in superalloys [4, 5]. It was reported about the influence of the cantilever tips
geometry as well as etching depth on an estimation of particle parameters in Waspaloy [5]. In the vi
present study, the very high resolution during measurements of non etched specimen has been oo
achieved; that led to leave out of account this phenomena. po
The local chemical composition of primary vy,’ precipitates has been determined with help of TEM-
EDS technique. The elemental maps of Waspaloy are shown in Fig. 5. The composition of y’, was
established as follows: (Nig 4;C0405sCrg04)3T1g63A10 37. Abstra
U.4um ar
Fig.5: TEM-EDS element maps of Waspaloy Be
Summary Sn
The combination of analytical TEM and AFM techniques is a powerful tool in stereological ;
characterisation of nickel-base superalloys. Because of the homogeneous distribution of nanometer 5
sized vy,’ particles, the estimation of microstructural parameters of Waspaloy is possible by TEM Howe
methods. The TEM quantitative analysis is a relatively easy procedure of practical importance. The ro
AFM measurements of a non etched specimen surface leads to a good agreement with the TEM se
analysis for the y ‚’ particle size but their density and volume fraction is overestimated applying Hin
simple stereological rules. Un
Acknowledgement NN
This work is part of the DFG - joint research programme “Herstellungs- und Lebensdauermodelle
fiir den Einsatz von Nickel-Basiswerkstoffen in Dampfturbinen oberhalb 700°C”. The financial Oo
support of the Deutsche Forschungsgemeinschaft is gratefully acknowledged. on
References =
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4) M. Goken, M. Kempf: Acta Materalia 47 (1999), 1043
5) A. Bourhettar, A. Hazotte, M. Troyon: Materials Characterization 34 (1995), 265
90
