Title: The influence of external factors on superplastic deformation of Al–Al₄C₃ composites

Authors: Michal Besterci, Frantisek Lofaj, Oksana Velgosova

Addresses: Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, Kosice 04353, Slovakia. ' Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, Kosice 04353, Slovakia. ' Technical University, Faculty of Metallurgy Department of Non-ferrous Material and Waste Treatment, Letna 9/A, Kosice 04200, Slovakia

Abstract: Deformation of the Al–Al₄C₃ composites with different volume fraction of Al₄C₃ phase was investigated at different temperatures (293–723 K) and different strain rates (2.5 × 10^-5 s^-1 – 1 × 10^-1 s^-1). At temperatures 673–723 K and at the highest strain rate of 10^-1 s^-1, a significant ductility increase was observed. TEM analysis suggests that it is the result of dynamic grain polygonisation, grain slip and rotation, partial recrystallisation and dislocation creep in the tested system, which is known as strain induced dynamic recovery. Increase of the volume fraction of secondary phase in the studied composite resulted in a shift in the deformation mechanism from more slip on grain boundaries to more grain rotation.

Keywords: composite materials; superplastic deformation; strain rate; TEM analysis; superplasticity; composites; temperature; strain rate; grain polygonisation; grain slip; grain rotation; partial recrystallisation; dislocation creep; mechanical alloying.

DOI: 10.1504/IJMPT.2005.006456

International Journal of Materials and Product Technology, 2005 Vol.22 No.4, pp.263 - 273

Published online: 10 Mar 2005 *

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