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Figure 1 - SEM image of a polished polycrystalline Ni-base superalloy. The complex microstructure has a polycrystalline structure, including twin grain boundaries and a high number of M23C6 carbides. The grain boundaries of the alloy are continuously occupied by carbide precipitation.

Figure 2 – Hardness (a) and elastic modulus (b) property maps. The inter-granular carbide is difficult to discern from the SEM image, but clear in the hardness map, where the carbide precipitation appears yellowish. The map of elastic modulus provides information on the elastic properties of the respective phases and grain orientation.

Property Mapping Ni-based Superalloys Nanoindentation is radically faster, easier, and more accurate than traditional microhardness testing, because the size of the indentation is determined directly from the relationship between force and penetration depth, both of which are measured continuously. From this data, material properties can be derived, such as elastic modulus and hardness. The software option NanoBlitz 3D enables fast and precise mapping of mechanical material properties by nanoindentation. Here, a grid is automatically produced from a series of indentations, with each of these indentations taking approximately 0.6 seconds.

The region shown in Figure 1 was tested with the NanoBlitz 3D method, using a grid of 80 x 80 indentations, for a total of 1600 indentations. The distance between the indents is 5 microns. The resulting grid is shown in Figure 1b. Each grid point includes information on the rigidity, hardness, and elastic modulus of the material. From this data, the desired material properties can be displayed in a property map.

Darius Tytko, Elektronen-Optik Service GmbH