Microstructural and Mechanical Properties of a Material Processed by Streamline Proposed Vortex Extrusion Die

Abstract

Vortex extrusion (VE), as a severe plastic deformation technique, uses a novel designed stationary die that imposes intense strain to the processed material. Materials in the VE process experience torsional deformation and simultaneous reduction in area. The amount and intensity of this additional deformation vary according to the radius moving from the center to the surface of the VE die due to variations in the path of the material through a radius proposed by the Beziers' formulation. In the present study, the VE die is designed through a streamline approach based on a cubic Beziers' formulation that was employed to investigate the microstructural and mechanical properties of the processed samples and to link the results to those obtained through a finite element analysis of this technique. The results of the microstructural characterization exhibit a higher fraction of high-angle grain boundaries of the VE processed samples compared to what can be achieved by conventional extrusion-processed. Consequently, a significant improvement was observed in tensile properties of the samples after SPD processing using the proposed streamlined VE die.