Effects of processing parameters on the fracture behaviour of cold roll bonded and accumulative roll bonded Al–Cu lamellar composites

Abstract

Al–Cu composites were fabricated by cold roll bonding (CRB) and accumulative roll bonding (ARB) processes. The effects of different parameters were investigated on the failure mechanism of the composites. A scanning electron microscope (SEM) and an optical microscope (OM) were used to characterise the microstructures of the resulting composites. The peeled surfaces of the CRBed material revealed that micro-cracks were formed almost perpendicular to the rolling direction and caused the premature failure of the bonding during the peeling test. Also, tensile, microhardness and shear punch tests were conducted on the Al–Cu composites produced under different conditions. Failure analysis of the non-heat-treated composites revealed that the layers separated from the middle of ARBed specimens. However, these centre-line separations were alleviated in composites subjected to heat treatment, even though the initiation of inter-lamellar micro-cracks were observed due to the formation of intermetallic compounds for heat-treated specimens.