Pressure Welding Through a Layer of Hydrocarbon Substance: Physical Processes of a Diffusion Joint Formation

Abstract

The article deals with the hypothesis on the diffusion-processes’ activation mechanisms during pressure welding with a pulsed current through the hydrocarbon-substance layer. Despite the developing this welding method in the last century, this topic is still insufficiently studied and, thus, needs further research. In the time of developing this welding method, the required amount of scientific data on the physical and chemical processes accompanying the formation of the joint did not exist. The article overviews the physicochemical processes dealing with the subject of the study of interdisciplinary research. Experimental studies carried out by specialists in different fields enabled establishing data necessary to develop the hypothesis. The nanoscale carbon formations were discovered, and their properties were studied. The phenomena accompanying the electric current in micropinches, ‘Coulomb explosions’ with the shock wave formation, the anomalous mass transfer under the shock loading during diffusion welding of different materials were investigated. As experimentally proved, the electroexplosive and electromagnetic phenomena, shock waves affecting the surface metal layers activate the diffusion processes. Based on a large number of interdisciplinary studies, a hypothesis on the formation of a diffusion joint during pressure welding with a pulsed current through the layer of hydrocarbon substance is formulated. The time of formation of a joint at the same temperature is lesser than that required for diffusion welding in vacuum. The structure of the welded joint is similar to the structure obtained by diffusion welding in vacuum.

Keywords

• pressure welding
• hydrocarbon substances
• electric explosion
• electric current
• nanotubes
• diffusion