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¿Es el diboruro de osmio un material ultra-duro?
Jun Yang1, Hong Sun, Changfeng Chen
1Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China.
Journal of the American Chemical Society
|May 16, 2008
Resumen
Los cálculos de los primeros principios revelan que OsB2 exhibe una fuerza de cizallamiento anisotrópica. Su alta resistencia al corte (001) [100] contribuye a su naturaleza ultra-dura, pero el corte débil (001) [010] limita algunas aplicaciones.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Materiales computacionales Ciencia de la ciencia.
- Física del estado sólido Física del estado sólido
Sus antecedentes:
- El diboruro de osmio (OsB2) representa una nueva clase de materiales ultra-duros.
- Estos materiales combinan elementos ligeros y covalentes con metales pesados de transición.
- Comprender los mecanismos de deformación es crucial para el diseño de nuevos materiales duros.
Objetivo del estudio:
- Para investigar la resistencia a la tracción y al cizallamiento ideales del OsB2.2 ortorrómbico.
- Para dilucidar los modos de deformación atomistic que rigen sus propiedades mecánicas.
- Para correlacionar las fuerzas calculadas con las observaciones experimentales de dureza.
Principales métodos:
- Los cálculos de los primeros principios se emplearon para simular el comportamiento mecánico.
- Se realizaron cálculos de resistencia a la tracción y al cizallamiento en la estructura ortorrómbica OsB2.
- Se analizó la anisotropía en la fuerza de cizallamiento en diferentes direcciones cristalográficas.
Principales resultados:
- Orthorhombic OsB2 exhibe una fuerza de cizallamiento altamente anisotrópica en el plano (001).
- La tensión de corte máximo fue significativamente mayor en la dirección (001) [100] (26,9 GPa) en comparación con la dirección (001) [010] (9,1 GPa).
- Las resistencias calculadas se alinean con la dureza experimental de Vickers de 30 GPa en el plano (001).
Conclusiones:
- La fuerte resistencia a la (001) [100] deformación de cizallamiento es responsable de la alta dureza de Vickers de OsB2.
- La resistencia de cizallamiento más débil (001) [010] limita su uso en aplicaciones abrasivas y de corte.
- La comprensión de los modos de deformación anisotrópica es vital para el diseño racional de materiales ultra-duros avanzados.
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