The study is concerned with the bonding mechanism in the cold pressure welding. The bonding mechanism consists of two main factors ; surface expansion causing the fracture of surface oxide films and adequate pressure buildup to establish the real contact area, this leading to the bonding between virgin materials.
In experiments, cold pressure welding for Al-Al, Cu-Cu, and Al-Cu is investigated under the condition of axisymmetric forging in a specially developed setup. Bonding strength is determined by notched tension test.
On the basis of a upper bound and slab methods, the theoretical bond strength is calculated as a function of deformation ratio. The theoretical results are in reasonably good agreement with the experimental ones in Al-Al bonding. As for Cu-Cu bonding, the experimental bond strength is considerably lower than the theoretical prediction due to the oxide film characteristics.
