The local mechanical properties of di †erent phases and grains in structural metallic alloys, composites and thin Ðlms determine their bulk properties and deformation behaviour. A nanoindenting atomic force microscope allows quantitative measurements of the local modulus of elasticity and the nanohardness with lateral resolutions of nearly 50 nm. Investigations on di †erent nickel-base superalloys (Waspaloy, CMSX-6), NiAl, c-TiAl and steels were performed, where their local mechanical properties could be determined separately on phases with lateral sizes down to 50 nm. With this measurement, the hardness of small cº-precipitates and of the matrix in the superalloys was determined. Other examples are given, where the local mechanical properties around a crack tip and across a grain boundary were determined. The load-displacement curves obtained for these specimens often show pop-ins similar to yield point phenomena. The estimated maximum shear stress under the indenter at this load level is comparable to the theoretical shear strength of the materials. The investigations show that the appearance of pop-ins depends strongly on the surface preparation conditions and the existence of oxide layers.
Investigations of thin gold Ðlms on glassy substrates of thickness 20-400 nm show an increasing hardness at lower indentation depths and higher hardness values of the thin Ðlms in comparison to bulk specimens.