Non-equal channel angular press bonding (NECAPB) as a novel severe plastic deformation technique: Bonding and interface

This study presents Non-Equal channel angular press bonding (NECAPB), a novel severe plastic deformation (SPD) technique developed to join similar and dissimilar metals, achieving exceptional bonding strength. NECAPB integrates non-equal channel geometry with plastic deformation and bonding, offering a mechanical and conceptual innovation not present in existing methods. This newly invented approach enables simultaneous grain refinement and metallurgical bonding within a single deformation path, offering new capabilities for billet processing. To evaluate the performance and effectiveness of the NECAPB process, a finite element simulation using Abaqus was conducted to investigate the effects of die geometry and process parameters on material flow and strain distribution. The simulation results were instrumental in optimizing the die design and predicting deformation behavior, thereby enhancing the process efficiency before experimental trials. Experimentally, aluminum billets were processed using the optimized NECAPB configuration and subjected to various mechanical and microstructural characterizations. Peel tests showed a maximum bonding force of approximately 710 N. Microhardness profiles across both longitudinal and transverse sections revealed significant strain hardening, with peak hardness reaching 75 HV in the bonded region and up to 94 HV near the billet-die interface. Field emission scanning electron microscopy (FE-SEM) of the bonded interface and fracture surfaces confirmed the quality of bonding and revealed ductile fracture features. Overall, the findings demonstrate that NECAPB is not just a bonding technique but a novel and versatile SPD process, offering improved mechanical performance, and the potential for broader application in advanced material processing.