High temperature instrumented microindentation: applications to thermal barrier coating constituent materials

Abstract

An original instrumented microindenter capable of testing materials up to 1000°C in an inert atmosphere has been developed. After describing the principle and its characteristics, the possibilities of the technique is illustrated with tests on NiAl(Pt) materials representative of the bondcoats of thermal barrier coatings. A modelling approach based on FEM calculations has been developed, which enables, by solving the inverse problem, to identify the variables of the constitutive law of the materials tested. Comparison of results thus obtained with published data when available shows a satisfactory agreement. This experimental technique, combined with the modelling approach, opens up a new way to determine the constitutive behaviour law of materials at a local scale and in a large temperature range.

Acknowledgements

We thank R. Bouchet for providing the NiAl(Pt) materials, M.-H. Ritti for AFM measurements, C. Babin for some of the microindentation measurements, M. Bejet for his technical contribution to the design and J.-L. Chaboche for helpful discussions. Part of this study was financially supported by DGA (Délégation Générale à l’Armement).