Micromechanical investigations of structural alloys
Our goal is to understand on a microstructural level the mechanical behavior of structural alloys using a combination of scanning electron microscopy, focused ion beam (FIB) machining and nanoindentation-based mechanical testing methods. In the given figure, we see an ion contrast image showing the anisotropic grain structure of a rolled Al-Li alloy sheet, along with SEM images of the FIB fabricated micro-column before and after compression testing and the corresponding engineering stress-strain curve.
"Determination of material parameters for component characterisation via indentation instrumentation testing"
New developments show that a multitude of material parameters for the description of elastic-plastic and/or visco-plastic material behaviour can be obtained via indentation instrumentation testing. Until now, these methods were successfully used in laboratory settings. For component characterisation, these methods have the advantage that material parameters can be obtained locally and nearly non-destructively at the surface of the component by measurement and analysis of the indentation curve.
The application of the method to components is not yet established, as components exhibit residual stresses; a property which is not yet considered to date in the methods. Aim of the work is to make the method ready for application to welded light-weight structures under consideration of residual stresses, as well as the special experimental conditions in components compared to laboratory specimens.