Present work has as objective to demonstrate the positive increase of the corrosion resistance throughparticular Ultra-Fine Grained (UFG) or Nano Crystalline (NC) structures obtained by Severe PlasticDeformation (SPD) on recently new developed -type Ti-25Ta-25Nb alloy. The alloy was processedby Accumulative Roll Bonding (ARB) method, applying four ARB cycles at ambient temperature. Themicro-structural characterization was performed before and after each ARB cycle, using XRD andSEM analysis. For all four structural states corresponding to ARB processed alloy (with 2, 4, 8 andrespectively 16 layers), has been determined the phase quantities for both detected -Ti and Tiphases, the lattice parameters values for each crystalline system of the present phases, and the averagecoherent crystalline domain size. The SEM analysis highlights the nano-grained character of thestructure obtained gradually by increasing the number of ARB cycles. Corrosion potentials are noblerand ennobled with the number of ARB cycles due to the favorable effect of the ARB processing;values of the corrosion current densities and of the corrosion rates are lower for ARB processed alloythan that of as-cast alloy and decrease with the increase of the number of layers confirming a moreprotective passive film; polarization resistances have higher values for ARB processed alloy, namely, abetter passivity. Values of the Tafel slopes show the anodic control of the corrosion process at theinterface between alloy and simulated physiological fluid. All these facts suggest the improvement ofprotective properties of the passive oxide layer, existing on the processed alloy surface. All corrosionparameters enhanced their values by the increase of the layer stacks, namely, the ARB processing has apositive influence on the alloy corrosion resistance. The increase of the number of ARB cyclesconducted to the thickening and stability in time of the alloy passive film.Int. J. Electrochem.
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