Browsing by Author "Pio, E."

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    Effect of Sn content on the passivity of Ti-Ta-Sn alloys
    (2023) Valverde, B.; Sancy, M.; Martinez, C.; Botello, E.; Pio, E.; Aguilar, C.
    In this work, Ti-13Ta-xSn samples were manufactured using the powder metallurgy technique with a porosity near 35 %. The microstructural analysis revealed that increased Sn content decreased the alpha-Ti and alpha'-Ti phases. Furthermore, scanning electron microscopy and X-ray photoelectron spectroscopy showed that the chemical composition of the passive oxide film was influenced by the Sn content. Moreover, the electrochemical analysis revealed that the protective properties of oxide film improved with the Sn addition.
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    Evolution of synthesis of FCC nanocrystalline solid solution and amorphous phase in the Ti-Ta based alloy by high milling energy
    (2021) Aguilar, C.; Pio, E.; Medina, A.; Martinez, C.; Sancy, M.; Guzman, D.
    Pure Ti and Ti-based alloys exhibit two equilibrium phases: at lower temperatures they have a hexagonal close packed (alpha-Ti) crystalline structure while at higher temperatures they possess a body-centered cubic (beta-Ti) structure. However, in special conditions, they could exhibit a metastable face-centered cubic (gamma-Ti) crystalline structure. This paper aims to investigate the influence of Sn amount and milling time on the formation of gamma-Ti phase on the Ti-Ta based alloy. Four alloys with compositions Ti-13Ta-xSn (x: 3, 6, 9 and 12 at. %) were obtained by high energy milling. The alloys were analyzed by X-ray diffaction patterns, transmission and scanning electron microscopy. For the Ti-13Ta-3Sn alloy, the beta-Ti phase is formed in greater quantity, similar to 70% at 100 h. For the Ti-13Ta-6Sn and Ti-13Ta-9Sn alloys, the phase that is in greater quantity is gamma-Ti, around 100% at 100h. The Ti-13Ta-6Sn alloy shows a greater tendency to form the gamma-Ti phase, since the quantity is close to 100% at 50 h milling time. Thermodynamic calculations are comparable with experimental data. The calculations were made using the MAAT software based on Miedema's model. The MAAT is a free software that can be download from www.rpm.usm.cl. (C) 2020 Elsevier B.V. All rights reserved.