Determination of Weld Interface Properties and their Effect on the Strength of Multi-Material Aluminium-Steel Joints

Abstract

Collision welding is a promising manufacturing approach for joining similar and dissimilar metals without thermally influenced strength loss. This capability unlocks new potential for lightweight construction. Among other things, components and welded joints can be made more filigree and load-optimised. Widespread industrial use of this technology is still limited by insufficient knowledge of the underlying joining mechanisms. In this paper, collision welding is applied to an aluminium-steel material combination of steel (DC04) and aluminium (AA6016). First, the welding process window for the material combination is determined on a special model test rig by varying the collision speed and the collision angle, the two main process parameters in collision welding. Shear tensile tests are then conducted to refine the weld process window, focusing on the region exhibiting the highest shear tensile strength values. Scanning Electron Microscope (SEM) images are used to analyse the weld zone, revealing the formation of four different metallographic structures in the joint zone of the welded samples. The area fractions of these structures are quantified and correlated with collision angles and corresponding shear tensile strength values.