The Effect of Crystal Anisotropy and Aziumuthal Indenter Orientation on the Indentation Hardness and Modulus of Single Crystlal Aluminum
Nanoindentation is a well-established method intensively used for over two decades. However, it is still challenging to interpret indentation hardness and modulus results of technical aluminum alloys. To improve the understanding of the indentation behavior of these materials the effect of the crystal orientation and the azimuthal indenter orientation on aluminum single crystals was investigated. Single crystal aluminum with (100), (110) and (111) orientations were investigated via Vickers nanoindentation (max. load 10 mN).
It was found that indentation hardness and modulus vary periodically with the azimuthal indenter orientation on (100)- and (110)-oriented surfaces (in addition to crystal anisotropy). It was possible to assign this to the combined effect of the indenter geometry (Vickers pyramid) and crystal symmetry both two- und four-fold. Furthermore, this effect could be quantitatively determined for aluminum single crystals (variation amplitude 1.8% and 2.6% of average indentation hardness and modulus respectively) for the first time.