Influence of hydrostatic Pressure in Cold-Pressure Welding

Summary Earlier work by Bay has shown the introduction of brittle surface coatings by electrochemical or chemical plating to be useful when roll bonding A-A. The coating layers fracture during deformation and decover virgin surfaces which extrude through the cracks and establish contact and metallic bonding to the adjacent surface. This paper presents a systematic study of the influence of hydrostatic pressure on the fracture of Various types of surface layers. By cold pressure welding AI-AI, Cu-Cu, Al-alloy-Al-alloy and Fe-Fe in simple upsetting the ductility of different coatings have been studied at lour different levels of hydrostatic pressure. The ductility of electrochemical matt Ni is very pressure sensitive, chemical M is somewhat less sensitive whereas hard chromium is almost brittle even at large pressures.