Un máximo en la resistencia del cobre nanocristalino
Jakob Schiøtz1, Karsten W Jacobsen
1Center for Atomic-Scale Materials Physics (CAMP), Department of Physics, Technical University of Denmark, DK-2800 Lyngby, Denmark. schiotz@fysik.dtu.dk
Science (New York, N.Y.)
|September 6, 2003
Resumen
La deformación plástica en el cobre muestra una resistencia máxima en tamaños de grano de 10-15nm. Esto ocurre debido a un cambio de la dislocación a los mecanismos de deslizamiento del límite del grano a medida que disminuye el tamaño del grano.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Materiales computacionales Ciencia de la ciencia.
- Nanotecnología La nanotecnología es la nanotecnología.
Sus antecedentes:
- Las propiedades mecánicas de los materiales nanocristalinos son altamente dependientes de sus características microestructurales.
- Comprender la relación entre el tamaño del grano y la resistencia del material es crucial para diseñar materiales avanzados.
Objetivo del estudio:
- Para investigar los mecanismos de deformación plástica en el cobre nanocristalino utilizando simulaciones a gran escala.
- Para determinar el efecto del tamaño del grano en la resistencia y la tensión de flujo del cobre nanocristalino.
- Para dilucidar los mecanismos microscópicos subyacentes responsables de los efectos observados de fortalecimiento o debilitamiento del tamaño del grano.
Principales métodos:
- Empleó simulaciones de dinámica molecular con tamaños de sistema de hasta 100 millones de átomos.
- Varió el tamaño del grano de las muestras de cobre nanocristalino entre 5 y 50 nanómetros.
- Analizó los cambios en los mecanismos de deformación en función del tamaño del grano.
Principales resultados:
- Se identificó un pico en la tensión de flujo y la resistencia del material en un tamaño de grano de 10 a 15 nanómetros.
- Se observó una transición en el mecanismo de deformación plástica dominante.
- La plasticidad mediada por la dislocación prevaleció en los granos más gruesos, mientras que el deslizamiento de los límites de los granos dominó en las regiones nanocristalinas.
Conclusiones:
- La resistencia del cobre nanocristalino exhibe un máximo en un rango específico de tamaño de grano (10-15 nm).
- Esta resistencia máxima se atribuye a un cambio fundamental en los mecanismos de deformación.
- Los resultados de la simulación proporcionan información sobre la dependencia del tamaño del grano de las propiedades mecánicas en metales policristalinos.
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