Surface nanocrystalline characteristics and corrostion resistance of β-type titanium alloy

A nanostructured surface layer was prepared on a biomedical TNZF alloy by surface mechanical attrition treatment (SMAT) for 30 min, and the effects of surface nanocrystallization on the corrosion resistance of TNZF alloy were studied. The surface nanocrystallization mechanism ascribes to a large amount of dislocation slips which can segment the grain and the crystalline refinement by the grain rotation. The electrochemical impedance spectroscopy tests in 0.9%NaCl solution show that the impedance of surface nanostructured alloy increases, compared with the coarse crystalline. The potentiodynamic polarization curves illustrate that the corrosion potential of this kind of Ti alloy by SMAT is higher than that with coarse crystalline and at the same time, the corrosion current becomes lower, and thus the corrosion resistance of the alloy to Cl^- is highly improved by surface nanocrystallization.