Nanoindentation tests for TiO2, MgO, and YSZ single crystals

Nanoindentation tests were performed for single crystals of TiO2, MgO, and YSZ (Yttria Satirized Zirconia) using a Berkovich indenter at room temperature. The indentation tests were performed in the load range from 500 to 1500 μN. The area function calibration was performed by using a standard fused SiO2 sample. There is no difference among the reduced moduli of TiO2, MgO, and YSZ, while the nanohardness of YSZ is larger than those of TiO2 and MgO. For YSZ, the reduced modulus along a [1 0 0] direction is larger than that along a [1 1 1] direction, which corresponds to the theoretical estimation using the elastic stiffness constants.