## 4 Conclusions  
This study introduced a novel hybrid SPD technique called Vo-CAP, which combines the advantages of both VE and ECAP processes in a single die. The innovative design features a unique integration of Vortex Extrusion and ECAP channels, complemented by a conical die geometry that enables efficient assembly and disassembly without traditional fasteners. This single-pass process configuration enhances its suitability for industrial implementation. Figure 21: OM images. (**a**) Annealed and (**b**) Vo-CAP-processed workpiece. The research methodology encompassed a comprehensive FEA, ANN, and NSGA-II algorithm and experimental studies. The process parameters were systematically optimized using a multi-objective approach that considered effective strain, pressing load, and strain inhomogeneity. The optimal design parameters were determined to be a twist angle of 166.33\({}^{\circ}\), twist length of 10.33 mm, and Transition Channel length of 34.2 mm. The optimization results were validated through both FEM analysis and experimental studies, showing excellent agreement. The experimental results demonstrated significant improvements in mechanical properties of AA6082 aluminum alloy:  
* Hardness increased to 113.2 HV, representing a twofold improvement compared to the annealed state;
* Ultimate tensile strength reached 415.75 MPa, and yield strength increased to 248 MPa;
* Material toughness was improved compared to the annealed state, demonstrating an enhanced energy absorption capability;
* OM images clearly show the homogeneous distribution of the annealed material. In addition, orientations were clearly seen in the OM images obtained as a result of the Vo-CAP process. Since the OM images were adequate to see a grain size reduction and grain orientations, another detailed microstructural analysis was not required in this study;
* The strain distribution showed improved homogeneity across the processed workpieces;
* The single-pass processing capability reduced processing time and energy consumption;
* The assembly and operation were simplified through the innovative conical die design. These results demonstrate that the Vo-CAP process represents a significant advancement in SPD techniques, showing effectiveness in enhancing the mechanical properties of AA6082 aluminum alloy through grain refinement. SPD methods generally result in very good mechanical properties, but what makes them more attractive than the conventional method is that the ductility of the material does not decrease after the process. Nevertheless, the fact that SPD processes are only suitable for small-scale materials appears to be the most significant challenge to their industrial application. Looking at the industrial uses of small aluminum alloys, they are used as fasteners such as nuts, bolts, and rivets, particularly in the aerospace industry. Considering, for example, that the operating conditions of an aircraft are \(-\)60 degrees at an altitude of 10,000 feet and +30 degrees on the ground, it is certain that increasing the mechanical life of these simple and cheap-looking fasteners will be an important gain in terms of reducing the time the aircraft spends in the hangar, if not in terms of fastener costs. For this reason, such methods are believed to have a great deal of potential for industrial applications. The alloy of choice for this study was AA6082, which is often the preferred alloy for SPD processes. And the Vo-CAP process was successfully completed. The literature shows that SPD studies have been successfully applied to various metallic parts including other aluminum alloys, copper, magnesium, steel, etc. Therefore, it will not be difficult to say that this method, which is presented in the literature as a new SPD method and offers ease of use and time saving, can be applied to other materials used in SPD studies. Consequently, while the current study focuses specifically on AA6082, future research could explore the potential applicability of this process to other metallic materials.