For a complete understanding of materials at the micro- and nanoscale, the correlation of various metrological techniques is required. Nanomechanical testing in combination with STEM, EBSD, EDX and high resolution SEM imaging creates new opportunities for material scientists. As a result, the geometry, grain morphology and dislocations can be observed as the sample is stressed towards its failure. This enables a direct quantification of various stress induced effects in materials.
Application Example: Correlative STEM and Nanomechanical Testing
STEM enables high resolution imaging by detecting transmitted electrons. This is achieved by installing a STEM detector into the SEM chamber, located below the sample. The FT-NMT03 In-Situ Nanomechanical Testing System has an optimized geometry for correlative measurements. The system does not feature a base plate that would obstruct or reflect the electron beam below the sample. Also, it features a compact design that leaves enough space for the detectors and enables imaging at a short working distance.Electrons which pass through the sample can be collected to produce a variety of transmission images, which give different insights into the sample. Bright-field imaging (BF) detects the electrons that have either not been scattered at all or have been inelastically scattered at very small angles. They largely exhibit crystallographic information. On the other side, High Angle Annular Dark Field (HAADF) imaging detects the electrons that have been elastically scattered to large angles. This indicate that they have passed very close to the atomic nuclei in the sample. The HAADF signal is directly proportional to the density and thickness (mass-thickness) of the specimen.By correlating STEM with tensile testing of thin sample, the effects of e.g. dislocation onto the mechanical behavior of the sample can directly be quantified.