Ultra-high speed X-ray radioscopy of jet formation during high-velocity impact welding of dissimilar metals

The welding of dissimilar metallic assemblies produced by high-velocity impact occurs at high strain rates ( i.e. , impact velocities) and various dynamic collapsing angles. However, the quality of the resulting weld surface depends on several parameters, one of which is the jet formation and particle cloud formation upon impact. This phenomenon arises from intense heat and pressure upon impact, playing a decisive role in determining the resulting weld quality. Here, the jet formation of such welds is described, providing new insights into the understanding of cold-welding methods. Jet formation plays a key role in generating the necessary conditions required to weld two dissimilar metal surfaces. Copper (Cu) and aluminum (Al) samples were subjected to high strain-rate loading using the single-stage gas gun available at ID19 beamline (ESRF, France) coupled with ultra-fast synchrotron X-ray radiography in order to investigate, in situ , the production, propagation, and evolution of jets upon impact of dissimilar metals. Several impact conditions (impact angle and material configuration) were investigated at an approximate impact velocity of 500 m/s. The results reveal that the jet size, speed, and morphology evolve differently as a function of the initial impact conditions. These results demonstrate, for the first time, a direct in situ investigation of jet dynamics and weld quality in impact welding of dissimilar metallic materials. • Synchrotron X-ray imaging reveals jet dynamics in dissimilar metal impacts. • Impact angle strongly influences jet morphology and propagation behavior. • Flyer–target material configuration controls jet angle and jet velocity. • Jet growth shows a linear relationship between jet length and time.