Pulsed-electric-current bonding of oxygen-free copper and austenitic stainless steel

Abstract

Although pure copper has good electrical and thermal conductivity, it is often used in combination with other metals due to its poor strength. An inexpensive austenitic stainless steel that has excellent corrosion resistance is a good joining material for pure copper, and the joining of these dissimilar metals enables the fabrication of parts for a wide range of applications. However, it is difficult to weld pure copper and stainless steel due to the large differences between their thermal properties. Therefore, in this study, the pulsed-electric-current bonding was applied to achieve solid state bonding of oxygen-free copper (OFC) and SUS304 austenitic stainless steel, and the bonding characteristics were investigated. The results show that the joint tensile strength improves with the increase in the bonding temperature and the applied pressure, and the sample bonded at 973 K with an applied pressure of 20 MPa exhibited a high strength of greater than 200 MPa, which caused a fracture in the OFC base material.