Combining circular-to-rectangular direct extrusion and equal channel angular pressing: Analysis and simulation

An experimental and numerical study of equal channel angular pressing (ECAP) as the most effective severe plastic deformation (SPD) process and circular-to-rectangular direct extrusion (CRDE) as traditional deformation process has been conducted as separate and combined processes, respectively. An analysis of the deformation mechanisms based on grain fragmentation due to the velocity discontinuities and corresponding shearing along them has been undertaken. To reveal the main aspects of the deformation processes in a comparative manner, a finite element analysis (FEA) is performed and the results are depicted in terms of strain distribution and working-load. Experimental tests have confirmed the FEA. To evaluate the improvement of the mechanical properties as effect of applying the two processing methods as separate and combined procedures, tensile tests are performed. An increase of the yield and tensile strength without a further reduction in ductility is found. The results of this study highlight the potential of combining CRDE and ECAP as an efficient processing route for production of high-performance materials.