Advancing cold roll bonding efficiency by preceding XHV-adequate laser deoxidation

The influence of a preceding laser ablation surface treatment on cold roll bonding (CRB) efficiency under extreme high vacuum-adequate (XHV-adequate) conditions were examined. Experimental investigations were conducted in a controlled glovebox environment. The impact of varying laser parameters on the critical reduction required for bonding copper and aluminium sheets was analysed. The results demonstrate a significant reduction in critical deformation necessary for bond formation. Surfaces treated by laser ablation achieve bonding at plastic deformations as low as 0.5%. In comparison, brushed surfaces require a plastic strain of 19% in similar XHV-adequate conditions. Using confocal laser scanning microscopy, a correlation between laser parameters and resulting surface characteristics was established, revealing material-specific surface alterations. Scanning electron microscopy analysis of the bonded interfaces further shows enhanced interfacial deformation in laser-treated specimens, which is characterised by increased waviness and pronounced protrusions. The investigations demonstrate a synergistic effect between laser-induced surface modifications and oxide-free conditions in an XHV-adequate atmosphere, which leads to a significant optimisation of CRB efficiency.