Nanoindentation study of single-crystal NaTh_2(PO_4)_3

摘要

The single crystals of sodium dithorium orthophosphate NaTh_2(PO_4)_3 (NThP) were studied by means of microanoindentation. The NThP hardness was found to be H_N=8.76±0.18 GPa and the elastic modulus E_N=144 ± 1 GPa. Microhardness anisotropy of the NThP crystal unequal faces is insignificant. The non-uniformity of plastic strain observed for the NThP is caused by fracture initiation and growth in the imprint. The average fracture toughness index (K_(Ic)) for the NThP is estimated to be equal to 0.56 MPa m~(0.5).