ABSTRACT
In a recently performed indentation experiment of a ball into a [001]-oriented single-crystal sample of fcc-structure, the rim of the remaining indentation crater appeared as a square rather than as a circle. We present the results of a refined analysis, which aims to elucidate this curious new phenomenon and its physical origin. The methodology is threefold: (i) On the experimental side, measurements with a scanning electron microscope equipped with a backscatter electron detector are performed to reconstruct a 3D-surface model of the indentation topography. (ii) On the numerical side, we investigate this problem in a finite element simulation with a phenomenological material model for anisotropic elastoplasticity. (iii) A kinematical explanation for the observed deformation pattern is proposed that operates on the micromechanical scale of plastic slip in the fcc single crystal.