Microstructure refinement and mechanical properties improvement of Al-Si-Fe alloys by hot extrusion using a specially designed high-strain die

Abstract

A heteromorphic extrusion die with right-angle corners in the die hole was designed in this study to give a high local strain to the extrudate metal during hot extrusion of Al-Si-Fe alloys, and the strain distribution in the extrudate metal was evaluated using the finite element method. It was demonstrated that the change in metal flow direction at the right-angle corners is effective for generating high strain in the extrudate metal and refining brittle inclusion particles such as primary Al 9 Si 2 Fe 2 (β phase) particles and eutectic Si particles. The refinement of these particles led to significant improvements in tensile elongation and plastic deformability in cold rolling of the alloys.