Deformation characteristics of a ductile material surface, impacted by erosive particles, was investigated at single impact sites. Surface of Cu-30% Zn (α-brass) was impacted by angular SiO 2 particles having an average size 5 and 25 μm in an evacuated experimental set-up. SEM and AFM studies were conducted to qualitatively and quantitatively characterize individual impact sites. Indent sizes were very small compared to grain size of polycrystalline α-brass. Even though the impacts occur at a 90 o angle, rather than symmetrical indent geometries, chip formation in specific directions within the individual grains is a very remarkable feature of the deformation observed. While cross-section of indents, within the same grains, exhibit almost identical material pile-up profiles and cut surface inclination, adjacent grains, apparently having different crystallographic orientation with respect to laboratory reference frame, reveal significantly different chip formation characteristics. It is proposed herein that the deformation path of particles is imposed by the mechanical response of the deforming grain. Because deformation is limited to a grain, anisotropic mechanical properties of a single crystal are correlated with directionality on chip formation and highly asymmetric indent geometries. Contrary to the previously proposed material removal mechanism for relatively larger particles, accumulation of strain does not appear to be the dominant mechanism in the case of impact with small (5-25 μm) particles. SEM and AFM results strongly support this explanation.