Combination of Nanoindentation and Microscopy for the Examination of Aluminum Alloys in Coarse- and Ultrafine-Grained Condition

When nanoindentation tests are performed on aluminum alloys, pile-ups can be observed in the area of the plastic deformation of the elastic-plastic indent. These pile-ups may have an impact on the actual contact area between indenter and sample and hence, have a significant influence on the measured mechanical properties. This work analyzed the pile-up behavior of a precipitation hardening (AA2024) and a solid solution strengthened (AA5182) Al wrought alloy in their coarse-grained and the ultrafine-grained condition. Here, the residual indents were examined using differential interference contrast light microscopy and scanning electron microscopy with secondary electrons as well as with electron backscatter diffraction capability. Micrographs of the hardness impressions were discussed in terms of the material pile-ups with respect to quality (deformation behavior) and quantity (actual contact area).