Deformation and removal characteristics of LiTaO_{3 single crystals in nanoindentation and nanoscratch}

The deformation and removal characteristics of lithium tantalate (LiTaO3) single crystal were investigated using nanoindentation and nanoscratch. During indenting, the occurrence of pop-in was associated with the transition of deformation from elastic to elasto-plastic. Slip bands were observed on the indented surface when the indentation load reached 4 mN. Slipping was along the crystal orientation of . Nanoscratch revealed that the threshold normal load for the transition of removal modes from ductile to brittle was 2.5 mN, corresponding to a scratch depth of 70 nm. Cracks were found along scratched grooves, which were likely induced by shearing. The removal rate in nanoscratch increased with the increase in normal load, but remained unchanged after the load was greater than 4 mN.