Publication: Estudio del efecto halógeno en la oxidación de aleaciones Ti-Al-V
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2011-04
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2011-04-29
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Abstract
El titanio y sus aleaciones tienen muy buenas propiedades, pero éstas se deterioran notablemente en aplicaciones de alta temperatura en las que se oxidan fácilmente. Se ha comprobado que pequeñas cantidades de elementos halógenos introducidos en la superficie de aleaciones intermetálicas de Ti-Al causan una importante mejora de las propiedades frente a la oxidación a altas temperaturas de estas aleaciones. Este efecto, conocido como efecto halógeno, no ha sido observado en aleaciones de Ti-Al-V. En este proyecto se pretende estudiar el efecto halógeno en muestras pulvimetalúrgicas y laminadas de la aleación Ti-6Al-4V, con el objetivo de encontrar una mejoría en el comportamiento a oxidación a alta temperatura. Las muestras pulvimetalúrgicas con las que se trabajó fueron fabricadas en el laboratorio a partir de polvos de aleación. El tratamiento de halogenación se realizó mediante la inmersión de las muestras en una mezcla polvos con un contenido de un 3% en peso de NH4Cl, a las temperaturas de 200°C, 600°C y 950°C. La resistencia a oxidación a alta temperatura de todas las muestras se evaluó mediante un tratamiento de oxidación a 600°C durante 300 horas. Finalmente, las muestras se analizaron mediante técnicas de difracción de Rayos – X y mediante análisis microestructural de secciones transversales, utilizando para ello un microscopio electrónico de barrido, MEB. ___________________________________________________________________________________________________________
Titanium and titanium alloys have very good properties, however they exhibit low oxidation resistance when exposed to high temperatures. It has been observed that when small quantities of a halogen element are implanted into the surface of Ti-Al intermetallic alloys their oxidation properties at high temperatures substantially improve. This effect, known as the halogen effect, has not been observed in Ti-Al-V alloys. This project aims to study the halogen effect in powder metallurgy and laminated samples of the Ti-6Al-4V alloy, in order to improve oxidation behavior at high temperature oxidation. The powder metallurgy samples used were manufactured in the laboratory from alloy powders. Halogenation treatment was performed by immersing samples in a powder mixture containing 3% wt of NH4Cl, at temperatures of 200 ° C, 600 ° C and 950 ° C. High temperature oxidation resistance of all samples was assessed by an oxidation treatment at 600 ° C for 300 hours. Finally, samples were studied by X Ray Diffraction and by the microstructural analysis of cross sections, using a scanning electron microscope, SEM.
Titanium and titanium alloys have very good properties, however they exhibit low oxidation resistance when exposed to high temperatures. It has been observed that when small quantities of a halogen element are implanted into the surface of Ti-Al intermetallic alloys their oxidation properties at high temperatures substantially improve. This effect, known as the halogen effect, has not been observed in Ti-Al-V alloys. This project aims to study the halogen effect in powder metallurgy and laminated samples of the Ti-6Al-4V alloy, in order to improve oxidation behavior at high temperature oxidation. The powder metallurgy samples used were manufactured in the laboratory from alloy powders. Halogenation treatment was performed by immersing samples in a powder mixture containing 3% wt of NH4Cl, at temperatures of 200 ° C, 600 ° C and 950 ° C. High temperature oxidation resistance of all samples was assessed by an oxidation treatment at 600 ° C for 300 hours. Finally, samples were studied by X Ray Diffraction and by the microstructural analysis of cross sections, using a scanning electron microscope, SEM.
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Oxidación, Aleaciones metálicas, Efecto halógeno, Pulvimetalurgia