Regularities of changes in chemical composition and microstructure of titanium nickelide upon high-dose ion-beam implantation of silicon into its surface were studied. It was shown that irradiation of a TiNi alloy with silicon ion beams results in formation of a surface oxide layer about six times thicker than that at the surface of the unirradiated alloy. The surface oxide layer of the ion-beam-modified alloy has an oxygen concentration which is ∼20% greater than that of the unmodified TiNi surface layer and lacks nickel, whose concentration is near zero to a sample depth of about 20 nm. Investigation of the near-surface region beneath the irradiated surface of TiNi samples by electron backscatter diffraction revealed that, under the action of a silicon ion beam, the near-surface region of individual B2-phase grains rising to the surface is fragmented with formation of a grain-subgrain structure with fragment (grain) sizes decreased down to 5 to 15 μm. It was suggested that grain orientation influences the observed effect.
- electron backscatter diffraction
- fragmentation of the near-surface microstructure
- high-dose ion implantation
- surface modification
- titanium nickelide
ASJC Scopus subject areas
- Materials Science(all)