Artigos
URI permanente para esta coleçãohttps://repositorio.fei.edu.br/handle/FEI/795
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Resultados da Pesquisa
- On the Interaction between Uniaxial Stress Loading and the Corrosion Behavior of the ISO 5832-1 Surgical Stainless Steel(2021-04-05) SANTOS, R. C. F. DOS; NAVILLE, W.; LIMA, N. B. DE; COSTA, I.; ANTUNES, R. A.© 2021, ASM International.The interaction between the uniaxial stress loading and the corrosion behavior of the surgical ISO 5832-1 stainless steel is addressed in the present work. Specimens were subject to uniaxial tensile and compressive stress at two different deformation levels (15 and 30%). The effect of the different loading modes and deformation levels on the residual stresses was investigated by x-ray diffraction. The composition of the passive films formed on each sample was assessed by x-ray photoelectron spectroscopy (XPS). The corrosion behavior was studied by electrochemical impedance spectroscopy and potentiodynamic polarization in phosphate-buffered solution at 37 °C. The semiconducting character of the passive films was determined by the Mott-Schottky approach. Our findings point to a positive effect of compressive loading on the corrosion resistance of the steel. The passive current density (ipass) decreased for the strained samples, especially for that subject to 15% compressive deformation for which ipass was 63% lower than for the as-received steel. The passive film formed at this condition presented strong Cr2O3 enrichment, according to XPS results. Moreover, the compressive stresses favored the formation of a passive film with fewer defects, decreasing the donors density. The results are discussed based on the correlation between residual stresses, passive film composition and its electronic properties.
- Effect of Niobium on Phase Transformations, Mechanical Properties and Corrosion of Supermartensitic Stainless Steel(2017) de Oliveira M.P.; Calderon-Hernandez J.W.; Magnabosco R.; Hincapie-Ladino D.; Alonso-Falleiros N.© 2017, ASM International.The influence of niobium addition in a supermartensitic stainless steel with 13Cr-5Ni-2Mo has been studied. The steel with Nb tempered at 600 °C for 2 h showed improved mechanical resistance properties and lower degree of sensitization, without compromising elongation and pitting corrosion resistance, when compared to the reference steel. In order to understand the Nb effect in such steel, mainly regarding phase transformation, different tempering time intervals have been studied. The better performance of the SM2MoNb is attributed to the hindering effect that Nb has in the kinetics of the phase transformations during tempering, delaying the precipitation start and coarsening stages of the present phases.