The influence of silicon on topographical parameters and mechanical properties of the Ti-Ni-Ta-Si surface alloy synthesized on the NiTi-substrates

This work comprises a study of the effect of silicon on the topographical parameters and mechanical properties of the Ti-Ni-Ta-Si surface alloy (SA) synthesized on the NiTi-substrates by the additive thin-film electron-beam method. It was found that the roughness of [Ti-Ni-Ta-Si]SA (∼0.095 μm) has a lower value than in [Ti-Ni-Ta]SA (∼0.195 μm). The values of the yield strength σ_y in the surface layers of [Ti-Ni-Ta-Si]SA and [Ti-Ni-Ta]SA are characterized by a gradient decrease from ∼4.2 GPa up to ∼1.2 and ∼1.7 GPa, respectively. During the indentation, evaluation of the deformation behavior (recovered elastic –ε _elast, and superelastic – εin the surface layers of_SE, residual plastic – ε_elast deformation) showed, that in surface layers of [Ti-Ni-Ta-Si]SA and [Ti-Ni-Ta]SA due to an increase of ε_elast, there was a decrease in ε_SE up to ∼35 and ∼22%, respectively (for the NiTi-initial ε_SE ≈ 38%). (paper)