The influence of external factors on superplastic deformation of Al-Al4C3 composites

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 x 10(-5) s(-1) - 1 x 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.