Resistance spot welding of dissimilar material joints with a cold gas sprayed inlayer

Abstract

Abstract In this publication, Cold-Gas-Spraying (CGS) is investigated as an enabler for mixed-material joints between aluminum die cast and steel components. By coating the aluminum substrate with a steel inlayer, welds can be performed between the steel joining partners. Thus, allowing the creation of a metallurgical bond between similar materials and a mechanical joint between dissimilar materials. During the resistance spot welding process, a reduction of defects in the porous inlayer surrounding the nugget is observable. With the use of an EBSD-analysis a recrystallization of the highly prestressed particles in the coating is noticeable which correlates with the reduction of hardness in the heat affected zone resulting in a metallurgical notch. Aluminum, with its lower melting point, will be liquefied during the welding process, resulting in a characteristic bloat. The contact between the liquid phase and the porous inlayer results in high requirements regarding the compactness of the cold-gas-sprayed inlayer.