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Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture
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El origen de la escisión del iridio en el iridio es quebradizo
Marc J Cawkwell1, Duc Nguyen-Manh, Christopher Woodward
1Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104-6202, USA. cawkwell@seas.upenn.edu
Science (New York, N.Y.)
|August 16, 2005
Resumen
El iridio y el iridio.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La metalurgia es la metalurgia.
- Mecánica de los Sólidos Mecánica de los Sólidos
Sus antecedentes:
- El iridio exhibe una escisión frágil única después de la deformación plástica.
- Comprender los mecanismos detrás de este comportamiento es crucial para la ingeniería de materiales.
Objetivo del estudio:
- Para investigar los mecanismos atomísticos responsables de la fragilidad de la escisión del iridio.
- Para aclarar el papel de las estructuras del núcleo de dislocación en la deformación plástica y la fractura.
Principales métodos:
- Se realizaron simulaciones atómicas utilizando un potencial de orden de enlace derivado de la mecánica cuántica.
- El análisis se centró en las estructuras del núcleo de la dislocación del tornillo y sus transformaciones.
Principales resultados:
- Se identificaron dos estructuras de núcleo de dislocación de tornillo: planar deslizante y metastable no planar.
- La transformación térmica entre estos núcleos conduce a altas tasas de deslizamiento cruzado.
- Esto da como resultado un rápido aumento de la densidad de dislocación y un importante endurecimiento del trabajo.
Conclusiones:
- La interacción entre las estructuras del núcleo de dislocación y el deslizamiento transversal atermal impulsa el endurecimiento por trabajo del iridio.
- Este mecanismo conduce naturalmente a la escisión de la fragilidad observada en el iridio.
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