Abstract

CALLISAYA, C. E.; SORIA, S  and  SOUL, H. Analysis of nitinol damage in wires by fretting. Revista Boliviana de Física [online]. 2016, vol.29, n.29, pp.17-22. ISSN 1562-3823.

We characterize the damage by fretting in nitrinol wires and discuss how the martensitic transformation affects that process, being such transformation typical of these allows which are widely used in biomedical industry given its super-elasticity. We have obtained an elas-ticity modulus with values 54 GPa and 30 GPa for the austenite and martensite phases respectively. For the characterization of the fretting damage we carried on tests with a variable normal load and with a normal constant load (P). For values of P between 16 N and 50 N we observed that for lower values of P there was an increment in the friction coeficient. For different load conditions and a displacement we observed MFR regimes for the values P = 50, 20 N; for these two values of P we found crack formations in the limit of the adherence and displacement zones (stick-slip), oriented along the displacement direction. For lower values of P there was an increment in the displacement contact area which yielded an increment of wear for P = 20 N The debris produced with both types of load had the same structure of . We finally observed the influence of the NiTi super-elasticity in the force vs. displacement graph as an additional tilt which corresponds to the stiffness of the martensitic transformation of nitinol.

Keywords : Mechanical properties of solids; Elasticity; Friction, tribology and ha.

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