The results of the so far performed investigations of Al-Cu butt cold pressure welding by the method of upsetting

The paper presents the results of the author's investigation obtained so far concerning the relationships between the properties of the Al-Cu weld and the surface condition prior to welding, the properties of the welded material and the process of plastic deformation of the materials being welded. The investigation performed has shown evolution modification of the geometrical structure of the surface and the layers below it during the approximation of the welded surfaces to each other. After the first physical contacts of the surface irregularities and their squashing, new irregularities of larger sizes arise as a result of the mechanism of plastic deformation of grains in the surface layer. The new geometrical structure of the surface thus formed has no features of similarity to the primary structure. It has been found that modelling of the approximation of the welded surfaces to each other, from the first physical contact of the surface irregularities to the distance of atomic force interaction in the methods of metal forming, should incorporate evolution change of the surface geometrical structure including the phenomenon of closing the voids. Initial computer simulations of the Al-Cu cold pressure welding process confirm the possibility of applying the finite element method (FEM) for the determination strains and stresses present in the welded materials.