Cold roll and indent vvelding of some metals

Abstract

The cold pressure welding of copper, brass, aluminium, and stainless steel has been investigated using thin-layer metal sandwiches produced by roll bonding and plane-strain indent welding. Shear tests were carried out to assess the level of bonding and scanning electron microscopy used to examine peeled surfaces from bonded specimens. Welding was found to be initiated by the formation of transverse cracks in the surface layers of the mating surfaces. These cracks coincide on both surfaces and are widened during deformation allowing extrusion of the base material through the cracks until a weld is formed. Extension of the surfaces is necessary for welding and the dependence of threshold deformation on the welding geometry is associated with the different surface behaviour. No recrystallization at interfacial regions was observed.