Deformation anisotropy of β-Sn crystals by microindenter

When a Vickers indenter is pressed into a surface of tin crystals, plastic strain below the impression distributes in a butterfly-like shape with open wings. The direction of principal shear strain changes greatly at regions under the impression toward the piled-up or the sunk-in surface. This finding suggests that the secondary slip system is activated following the primary slip system under the indenter, as it is penetrated. Observation using the etch-hillock technique supports the idea that dislocation substructure is formed just under the impression due to this mechanism.