Bonding characteristics of aluminium laminates and aluminium–graphite composites processed by roll bonding

Abstract

Roll bonding is a solid-state welding process, employed to join similar and dissimilar metals. Roll bonding with secondary particles in-between and accumulating the roll bonded material multiple times is an alternative method for manufacturing high-strength composites. In the current work, commercially pure aluminium strips are roll bonded at room temperature to 400 °C. The percent reduction varied from 10% to 70%, with an increment of 10%. Moreover, the aluminium strips are roll bonded with graphite particles dispersed in between (Al–Gr–Al). The aim is to study the effect of graphite particles on bonding behaviour. The critical process parameters such as the effect of temperature and percentage reduction on the bond strength are determined. The lap shear test is used to evaluate the bond strength. It is observed that the dispersion of graphite particles in between aluminium significantly increased the threshold reduction required for bond establishment. The threshold reduction decreases for roll-bonding aluminium with increasing temperature. Furthermore, it is observed that the bond strength significantly increases with increasing processing temperature. However, roll bonding with the graphite particles dispersed in between reduced the bond strength, and the effect was significant with increasing temperature. The bond strength of both Al and the Al–Gr–Al composites increases by increasing the reduction percentage. The de-bonded sample surfaces are analyzed using a scanning electron microscope. It is worth mentioning that the experimental outcomes of the current study predict the roll bonding parameters for the successful fabrication of an Al/Gr composite by accumulative roll bonding.