Microstructure and mechanical properties of AA1050/AA6061 multilayer composites via accumulative roll bonding and cryorolling and subsequent aging

AA1050/AA6061 multilayer composites were processed by combining accumulative roll bonding (ARB) and cryorolling, followed by aging. The microstructure evolution and mechanical properties of the multilayer composites were analyzed. The results show that cryorolling can enhance the mechanical properties of AA1050/ AA6061 multilayer composites compared to ARB. Cryorolling first improves the interfacial flatness and delays the onset of plastic instability, enhancing the deformation uniformity between the constituent layers. Second, cryorolling can accumulate a higher dislocation density and achieve a remarkable grain refinement. Moreover, cryorolling significantly reduces the formation of delamination and promotes the quality of the bonding interface between layers. The combined effect of high dislocation density, uniform deformation ability, and good inter-facial bonding gives cryorolled samples a considerably higher ultimate tensile strength than ARBed samples following peak aging treatment at multiple aging temperatures. Meanwhile, both the ARBed and ARB + cry-orolled samples exhibit the best performance after aging at 100 degrees C. The increase in the ultimate tensile strength of AA1050/AA6061 multilayer composites at peak aging is mainly attributed to ultrafine grains and fine pre-cipitates in the AA6061 layer.

Automated summary

AA1050/AA6061 multilayer composites were processed using a combination of accumulative roll bonding (ARB) and cryorolling, followed by aging treatment. The study analyzed the evolution of microstructure and mechanical properties of the composites. The results revealed that cryorolling improves the mechanical properties by enhancing interfacial flatness, delaying plastic instability, accumulating higher dislocation density, achieving grain refinement, reducing delamination, and promoting bonding interface quality. Cryorolled samples exhibited significantly higher ultimate tensile strength compared to ARBed samples after peak aging. Both ARBed and ARB + cryorolled samples showed optimal performance after aging at 100 degrees C. The increase in ultimate tensile strength in AA1050/AA6061 multilayer composites at peak aging is mainly due to the presence of ultrafine grains and fine precipitates in the AA6061 layer.