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Resistencia y mecanismo de ruptura de los nanotubos de carbono de paredes múltiples bajo carga de tracción
1Department of Physics, Washington University in St. Louis, CB 1105, St. Louis, MO 63130, USA. Zyvex LLC, Suite 200, 1321 North Plano Road, Richardson, TX 75081, USA. Department of Materials Science and Engineering, University of Wisconsin, 1509 Uni.
Science (New York, N.Y.)
|January 29, 2000
Resumen
Este estudio midió la resistencia a la tracción de los nanotubos de carbono de paredes múltiples (MWCNT), encontrando resistencias de 11 a 63 GPa. La falla de la capa más externa reveló altos valores de módulo de Young, cruciales para las aplicaciones de la ciencia de los materiales.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- Ingeniería Mecánica Ingeniería Mecánica
Sus antecedentes:
- Los nanotubos de carbono de paredes múltiples (MWCNT) poseen propiedades mecánicas excepcionales.
- Comprender la resistencia a la tracción precisa y el módulo de Young de los MWCNT individuales es fundamental para su aplicación en materiales avanzados.
- Estudios anteriores han proporcionado propiedades a granel, pero el comportamiento individual de los nanotubos bajo estrés requiere una investigación detallada.
Objetivo del estudio:
- Para medir con precisión la resistencia a la tracción y el módulo de Young de MWCNTs individuales.
- Investigar los mecanismos de falla de las MWCNT bajo carga de tracción.
- Para caracterizar la integridad estructural de MWCNTs en la nanoescala.
Principales métodos:
- Utilizó una etapa de nanostressing dentro de un microscopio electrónico de barrido (SEM) para experimentos de carga de tracción in situ.
- Experimentos de carga de tracción grabados en MWCNTs individuales utilizando video.
- Analizó las curvas de tensión-deformación derivadas de los experimentos.
- Examinó fragmentos de nanotubos fracturados utilizando microscopía electrónica de transmisión (TEM).
Principales resultados:
- La resistencia a la tracción medida de la capa más externa de MWCNTs varió de 11 a 63 gigapascals (GPa) para 19 nanotubos probados.
- Determinado el módulo de Young (E) de la capa más externa para estar entre 270 y 950 GPa.
- El fallo observado se produjo en la capa más externa, consistente con un mecanismo de "espada en vaina".
- El análisis TEM reveló diversas estructuras de fractura, incluidas cintas de nanotubos, patrones de onda y colapso radial parcial.
Conclusiones:
- Los MWCNT individuales exhiben una alta resistencia a la tracción y el módulo de Young en su capa más externa.
- El modo de falla "espada en vaina" es característico de la falla de tracción MWCNT.
- Las variaciones estructurales observadas en los fragmentos fracturados proporcionan información sobre el comportamiento mecánico de los nanotubos y los modos de falla.
- Estos hallazgos son vitales para el diseño y la aplicación de compuestos y dispositivos basados en nanotubos de carbono.
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