In situ electron backscatter diffraction (EBSD) during the compression of micropillars

For the first time, in situ electron backscatter diffraction (EBSD) measurements during compression experiments by a modified nanoindenter on micron-sized single crystal pillars are demonstrated here. The experimental setup and the requirements concerning the compression sample are described in detail. EBSD mappings have been acquired before loading, under load and after unloading for consecutive compression cycles on a focused ion beam (FIB) milled GaAs micropillar. In situ EBSD allows for the determination of crystallographic orientation with sub-100 nm spatial resolution. Thereby, it provides highly localized information pertaining to the deformation phenomena such as elastic bending of the micropillar or the formation of deformation twins and plastic orientation gradients due to geometrically necessary dislocations. The most striking features revealed by in situ EBSD are the non-negligible amount of reversible (elastic) bending of the micropillar and the fact that deformation twinning and dislocation glide initiate where the bending is strongest. Due to this high spatial and orientation resolution, in situ EBSD measurements during micromechanical testing are demonstrated to be a promising technique for the investigation of deformation phenomena at the nano- to micro-scale.