Mechanical and microstructural performance of convex dies in axisymmetric extrusion-Theory and experimental verification

An analysis of the convex die performance in the process of direct extrusion of 6063 and 2014 aluminum alloys is presented. Theoretical analysis of metal flow through convex dies and an optimization procedure using a proposed numerical model are complemented by the results of experimental verification. The proposed model is based on the upper bound theory and allows process parameters optimization. The optimized process parameters were then verified experimentally. Additionally, microstructure results for the profiles extruded under different processing conditions are presented and analyzed for the conditions responsible for formation of the peripheral coarse grain structure.