Influence of die geometric parameters on plastic flow of layer composites during extrusion process

An analysis of the co-extrusion of layered composite (core–sleeve system) using various dies (mainly convex dies) is presented in this study. In order to determine the influence of the die geometry on the flow pattern of layered composite, experimental studies using metallic modelling material were carried out. The initial composite materials (billets) with different volume fraction of the components, their various arrangements in the billet, different yield stress ratios and extrusion ratios were applied. Based on the analysis of the grid distortion, the range of deformation zones and relative velocity distribution in the outlet region, the best convex die geometry in comparison with others has been proposed. Based on the experimental study, the dependence of maximum extrusion load on the angle of the die was determined. The results showed that using convex dies with a specific geometry selected for a layer composite cause, among other things, better equalisation of particle velocity in a die outlet.