Evolution of microstructure and mechanical properties in 2014 and 6063 similar and dissimilar aluminium alloy laminates produced by accumulative roll bonding

Abstract Aluminium laminates of AA6063, AA2014 monomaterials and AA6063/AA2014 composites were produced by accumulative roll bonding processed up to 6 cycles. The microstructure was studied using electron backscatter diffraction and transmission electron microscopy. It is shown that 6 cycles lead to an ultrafine grained microstructure. The mechanical properties were studied by tensile testing and microhardness measurements. In AA6063 laminates, the strength goes over a maximum at 2 cycles, while in AA2014 it increases up to cycle 2 and then remains almost constant. The laminated composite reaches its highest strength after 1 cycle and then slightly decreases. Microhardness measurements were done to compare the deformation in the layers of the laminated monomaterials with those of the laminated composites. Differential scanning calorimetry was used to study the precipitate evolution and its effect on the mechanical properties during accumulative roll bonding. The strength results are discussed with regard to solid solution, precipitation, dislocation and grain size hardening.