Crystallographic texture role on the electrochemical property improvement contributed by grain refinement for AA2024 aluminum alloy subjected to cross accumulative roll bonding

Abstract

Herein, the synergistic influences of grain refinement and crystallographic texture development on the electrochemical behavior of the nanostructured AA2024 aluminum alloy were systematically investigated in a phosphate buffer solution (pH = 8.3). For this purpose, AA2024 alloy sheets were severely deformed at room temperature through cross accumulative roll bonding (CARB), i.e., each cycle was followed by a 90° rotation around the normal direction (ND) axis. The microstructure of the CARB-processed alloy after the eighth cycle showed a uniform structure with ultrafine grains with sizes of 150–100 nm. The dominant texture components became more intense at their initial cycles, but as the number of CARB cycles increased, the components became stable. Texture components such as S {123}< 634 > , Brass {011}< 211 > , Goss {011}< 100 > , Rotated Cube {001}< 110 > , and P {110}< 221 > were predominant after eight cycles. Moreover, it was revealed that the decreasing grain size and uniform distribution of extremely fine grains and high-intensity {011} orientation textures, such as Brass {011}< 211 > , Goss {011}< 100 > , and P {110}< 221 > texture components, had a positive role in the electrochemical responses of the AA2024 alloy with the increase of CARB cycles. Finally, these findings suggest that cross accumulative roll bonding processing can effectively condition a thick and less defective passive layer with superior protection properties.