Microstructure evolution of the nanostructued Al-Cu alloy produced by equal-channel angular pressing

K. Kassis, J. Masmoudi, M. Khitouni*, A. Kolsi, N. Njah

Laboratoire de Métallurgie Appliquée, Faculté des Sciences, B.P. 763 Sfax, 3018, Tunisia

* Corresponding author. E-mail: khitouni@yahoo.fr

Received : 14 April 2004; revised version accepted : 18 February 2005

Abstract

Microstructural changes of Al-Cu alloy of second melting associated with equal-channel angular pressing have been investigated using XRD, SEM, OM and TEM. In the quenched alloy after aging for 6 h at 500 °C, only Al8Fe2Si precipitates are observed. After pressing, plastic deformation occurs preferentially in these material, prior to grain refinement. The deformed structure is consisted of some areas where the grains were essentially equiaxed (Z-plane) and other areas where the grains were elongated (X and Y-planes). TEM observation in the X-plane shows a layered microstructure with a maximum thickness around 150 nm. By comparing the DSC measurements of the different samples, we have shown that the GP zones are dissolved during equal-channel angular pressing and the precipitation of q ’ and q phases is enhanced in the deformed sample.

Keywords: Severe Plastic Deformation; Grain refinement; Heating treatment.

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