High-velocity impact bonding of aluminum sheet to ceramic substrate via Vaporizing Foil Actuator

Vaporizing Foil Actuator Welding (VFAW), an explosives-free, high-velocity impact joining technique, was applied to direct metal–ceramic bonding and its feasibility and mechanism were assessed. An Al flyer reached 726 m/s, and impacted Si 3 N 4 at a 15° collision angle. Cross-sectional observations of the as-joined state revealed a macroscopically continuous interface without voids or macroscopic cracks, and no macroscopic cracking of the Si 3 N 4 substrate was detected. EBSD identified a fine-grained band on the Al side that remained continuous and adherent along the Si 3 N 4 surface. High-resolution TEM/STEM–EDS analysis showed no continuous oxide or diffusion layer at the interface within the detection limit, while revealing localized Al filling of nanoscale crack-like openings. Numerical simulations reproduced a leading-edge metal jet and plastic localization on the Al side and indicated that the temperature could transiently exceed the Al melting point. These results indicate Al inflow into submicrometer cracks, consistent with transient local melting (or highly softened flow) followed by rapid solidification. Overall, the joining mechanism is analogous to that of explosive welding in terms of metal jetting and high-pressure impact, while eliminating the use of explosives. In contrast to conventional explosive welding, VFAW allows the impact velocity and collision angle to be treated as active design variables that can be tuned via the electrical input energy, stand-off, and tool geometry, which is advantageous for brittle ceramics with narrow damage tolerances. The present process offers low energy input, high controllability, and improved operational safety, indicating its potential applicability to power-electronics substrates and heat-spreading components. • Detonation-free VFAW achieves continuous Al–Si 3 N 4 bonding without voids, macrocracks, or ceramic chipping. • Experiments and SPH simulations reveal an explosive-welding-like mechanism with metal-jet self-cleaning, Al DRX, and localized Al inflow without a continuous reaction layer above the detection limit of STEM–EDS. • Independent control of impact velocity and angle makes this process effective for crack-free bonding between metals and brittle ceramics.