| Revista: | Materials research |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000312836 |
| ISSN: | 1516-1439 |
| Autores: | Almeida, Luciano Henrique de1 Pires, Kelly Cristina Cezaretto Grandini, Carlos Roberto Florencio, Odila2 |
| Instituciones: | 1Universidade Estadual Paulista "Julio de Mesquita Filho", Faculdade de Ciencias, Bauru, Sao Paulo. Brasil 2Universidade Federal de Sao Carlos, Departamento de Fisica, Sao Carlos, Sao Paulo. Brasil |
| Año: | 2005 |
| Periodo: | Jul-Sep |
| Volumen: | 8 |
| Número: | 3 |
| Paginación: | 239-243 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Nota breve o noticia |
| Enfoque: | Experimental |
| Resumen en inglés | Impurity interstitial atoms present in metals with BCC structure can diffuse in the metallic matrix by jumps to energetically equivalent crystallographic sites. Anelastic spectroscopy (internal friction) is based on the measurement of mechanical loss or internal friction as a function of temperature. Due to its selective and nondestructive nature, anelastic spectroscopy is well suited for the study of diffusion of interstitial elements in metals. Internal friction measurements were made using the torsion pendulum technique with oscillation frequency of a few Hz, temperature interval from 300 to 700 K, heating rate of about 1 K/min, and vacuum better than 10-5 mbar. The polycrystalline Nb and Ta samples used were supplied by Aldrich Inc. The results obtained showed thermally activated relaxation structures due to stress-induced ordering of oxygen atoms around the Nb (or Ta) atoms of the metallic matrix. The results were interpreted by three methods and led to activation enthalpy values for the diffusion of oxygen in Nb and Ta of 1.15 eV and 1.10 eV, respectively |
| Disciplinas: | Ingeniería, Física y astronomía |
| Palabras clave: | Ingeniería metalúrgica, Física atómica y molecular, Difusión, Niobio, Tantalio, Estructuras, Entalpía |
| Keyword: | Engineering, Physics and astronomy, Metallurgical engineering, Atomic and molecular physics, Diffusion, Niobium, Tantalum, Structures, Enthalpy |
| Texto completo: | Texto completo (Ver HTML) |
