Lattice structure transformation and change in surface hardness of Ni3Nb and Ni3Ta intermetallic compounds induced by energetic ion beam irradiation

Ni3Nb and Ni3Ta intermetallic compounds, which show the complicated lattice structures were irradiated with 16 MeV Au5+ ions at room temperature. The X-ray diffraction measurement revealed that the lattice structure of these intermetallic compounds changed from the ordered structures to the amorphous state by the ion irradiation. The irradiation-induced amorphization caused the increase in Vickers hardness. The result was compared with our previous results for Ni3Al and Ni3V, and was discussed in terms of the intrinsic lattice structures of the samples.