AluminumAluminum is widely used across various industriesIndustry due to its low density, high ductility, and excellent corrosion resistanceCorrosion resistance. However, its primary production is highly energy-intensive, necessitating the development of sustainable recyclingRecycling methodsSolid-state recycling. Solid-state recyclingRecycling (SSR) has emerged as a promising alternative, offering the potential to significantly reduce energy consumptionEnergy consumption compared to conventional remelting processes. For SSR to be effective, the key challenge of disrupting the stable aluminumAluminum oxide (Al₂O₃) layers that form on the surfacesSurface of aluminum chipsAluminum chips during machining has to be overcome. Two primary SSR approaches exist: Severe plastic deformation (SPD) and field-assisted sinteringField-assisted sintering technology (FAST). SPD relies on high strain to mechanically break the oxide layers, while FAST uses diffusion mechanisms to overcome the oxide barrier without the need for mechanical deformation. Nevertheless, the exact bonding mechanisms, especially how the oxide layers are effectively disrupted in each process, remain unclear. This study investigates the bonding mechanisms in SPD and FAST using light and electron scanning microscopy together with energy dispersive X-ray analysis. The results reveal the critical roles of strain in SPD and reveal a newly developed, chemical disruption mechanism in FAST, leading to the necessity of additional plastic deformation after FAST to achieve adequate mechanical propertiesMechanical properties.