Accumulative roll bonding of aluminum alloys 2219/5086 laminates: Microstructural evolution and tensile properties

The present study describes the course of microstructure evolution during accumulative roll bonding (ARB) of dissimilar aluminum alloys AA2219 and AA5086. The two alloys were sandwiched as alternate layers and rolled at 300 °C up to 8 passes with 50% height reduction per pass. A strong bonding between successive layers accompanied by substantial grain refinement (∼200–300 nm) is achieved after 8 passes of ARB. The processing schedule has successfully maintained the iso-strain condition up to 6 cycles between the two alloys. Afterwards, the fracture and fragmentation of AA5086 layers dominate the microstructure evolution. Mechanical properties of the 8 pas ARB processed material were evaluated in comparison to the two starting alloy sheets via room temperature tensile tests along the rolling direction. The strength of the 8 pass ARB processed material lies between that of the two starting alloys while the ductility decreases after ARB than that of the two constituent starting alloys. These differences in mechanical behavior have been attributed to the microstructural aspects of the individual layer and the fragmentation process.

► Excellent interface bonding and substantial grain refinement after ARB. ► Iso-strain up to 8th pass. ► Different deformation response of two alloy layers after 7th pass. ► Fracture of AA5086 layers, formation of composite microstructure. ► Strength and ductility influenced by composite microstructure.