Experimental investigation and numerical simulation of plastic flow behavior during forward-backward-radial extrusion process

Finite element method was employed to investigate the effect of process parameters of plastic deformation behavior in Forward-Backward-Radial Extrusion (FBRE) process. The result of an axisymmetric model shows that the friction between die components and the sample has a substantial effect on the material flow behavior. Although strain heterogeneity index (SHI) slightly decreases with an increase in friction, large portion of the sample experiences significant strain heterogeneity. Increasing the friction factor also localizes the strain heterogeneity effect in the backward section, and spread the effect in the forward section. Decreasing the friction in the FBRE process can reduce the amount of the strain heterogeneity in the product while decreases the required punch force substantially. Furthermore, an increase in gap thickness increases the deformation in the area close to the lower punch at the expense of the area in the vicinity of the upper punch. The numerical simulation has a good agreement with the experimental results which confirms the accuracy of the proposed finite element model.