Cobre nanocristalino y ultrafino obtenido por molienda mecánica
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Rodríguez Baracaldo, Rodolfo
Benito Páramo, Jose Antonio
Cabrera Marrero, José María
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2010
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Este artículo presenta un método de obtención y caracterización de muestras masivas de cobre con tamaño de grano ultrafino (inferior a 1 μm) y nanocristalino (inferior a 100 nm). La fabricación del cobre se realiza inicialmente por el método de molien- da/aleado mecánico, obteniendo un polvo de estructura nanocristalina que posteriormente es consolidado por medio de un proceso de compactación en tibio a alta presión. El cobre masivo es sometido a caracterización microestructural analizando la evolución del tamaño de grano durante todas las etapas del proceso de fabricación, determinando las condiciones necesarias para desarrollar muestras en una amplia gama de tamaños de grano. La caracterización mecánica indica un incremento en la microdureza hasta valores de 3,40 GPa para el polvo NC sin consolidar. La resistencia a compresión se ve incrementada al re- ducir el tamaño de grano, obteniendo un límite elástico de 650 MPa para consolidados con tamaños de grano de ~62 nm.
This article presents a method for the sample preparation and characterisation of bulk copper having grain size lower than 1 μm (ultra-fine grain) and lower than 100 nm grain size (nanocrystalline). Copper is initially manufactured by a milling/alloying me- chanical method thereby obtaining a powder having a nanocrystalline structure which is then consolidated through a process of warm compaction at high pressure. Microstructural characterisation of bulk copper samples showed the evolution of grain size during all stages involved in obtaining it. The results led to determining the necessary conditions for achieving a wide range of grain sizes. Mechanical characterisation indicated an increase in microhardness to values of around 3.40 GPa for unconsolida- ted nanocrystalline powder. Compressivee strength was increased by reducing the grain size, thereby obtaining an elastic limit of 650 MPa for consolidated copper having a ~ 62 nm grain size.
This article presents a method for the sample preparation and characterisation of bulk copper having grain size lower than 1 μm (ultra-fine grain) and lower than 100 nm grain size (nanocrystalline). Copper is initially manufactured by a milling/alloying me- chanical method thereby obtaining a powder having a nanocrystalline structure which is then consolidated through a process of warm compaction at high pressure. Microstructural characterisation of bulk copper samples showed the evolution of grain size during all stages involved in obtaining it. The results led to determining the necessary conditions for achieving a wide range of grain sizes. Mechanical characterisation indicated an increase in microhardness to values of around 3.40 GPa for unconsolida- ted nanocrystalline powder. Compressivee strength was increased by reducing the grain size, thereby obtaining an elastic limit of 650 MPa for consolidated copper having a ~ 62 nm grain size.