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Desorden en las aleaciones icosaédricas Al-li-cu y Al-mn-si

P A Heiney, P A Bancel, P M Horn

Science (New York, N.Y.)

|October 30, 1987

Resumen

La dispersión de rayos X de alta resolución revela que las dendritas facetadas icosaédricas de aluminio-litio-cobre (AlLiCu) exhiben un trastorno atómico significativo. Las anchuras de pico en estos materiales son comparables a las aleaciones de Al-Mn-Si, lo que sugiere orígenes similares para sus propiedades estructurales.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
Física del estado sólido Física del estado sólido
La cristalografía es una técnica de cristalografía.

Sus antecedentes:

Los cuasicristales icosaédricos, como AlLiCu, poseen simetrías únicas de largo alcance.
Comprender el desorden atómico es crucial para explicar sus propiedades físicas.

Objetivo del estudio:

Para investigar las características estructurales de las dendritas AlLiCu icosaédricas facetadas.
Para analizar el desorden atómico y su impacto en los patrones de difracción.

Principales métodos:

Se empleó la dispersión de rayos X de alta resolución.
Análisis de patrones de difracción y morfología macroscópica.

Principales resultados:

Las muestras mostraron simetría icosaédrica de largo alcance tanto en difracción como en morfología.
A pesar de las facetas bien definidas, se observó un alto grado de desorden atómico.
Las anchuras de los picos de Bragg se escalaban linealmente con G perpendicular (momento de fase) y eran similares a las aleaciones icosaédricas de Al-Mn-Si.

Conclusiones:

El estudio aclara la compleja interacción entre la forma macroscópica y el trastorno a nivel atómico en AlLiCu.icosahedral.
Los hallazgos sugieren mecanismos comunes que gobiernan el desorden en diferentes aleaciones icosaédricas.

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