Auger Microanalysis of Surface Film on Diffusion Welded Interface

Study on Surface Film on Diffusion Welded Interface (Report 1)

Abstract

The surface film of weld parts is a very important factor affecting the weld characteristics of diffusion welds. It is desirable to clarify the behavior of the surface film on the diffusion welded interface. In this study, the surfaces before and after diffusion welding were observed with Auger electron spectroscopy. Composition and thickness of the welding surface, and the relation between change of surface composition by diffusion welding and tensile strength of welded joints are investigated. The following results were obtained.
1) The films of the welding surface of aluminum, copper, iron and SUS 304 stainless steel are composed of oxygen, carbon and base metal.
2) Composition and thickness of the surface films of various materials do not so much depend on the surface treatment such as the degreasing with acetone and the annealing in a vacuum.
3) The surface film along the welded interface of aluminum does not change during diffusion welding, but those of copper, iron and SUS 304 stainless steel disappear.
4) When the surface film disappears during diffusion welding, metallic bonding is formed at intimate contact area along the welded interface. The stability of the surface film has an influence on tensile strength of welded joints.
5) The segregation of sulfur is observed on no-contact surface along the welded interfaces of copper, iron and SUS 304 stainless steel, but it does not have much effect on tensile strength of welded joints.