Effect of Accumulative Roll Bonding (ARB) strain path on microstructural evolution and crystallographic texture development in aluminium

Abstract

In the present study nine successive ARB cycles were applied on double-layer 1 mm aluminum sheets following three different routes; normal, reverse and cross. Severely deformed sheets were studied by XRD and EBSD to show the evolution of crystallographic textures, while mechanical properties are characterized by micro-tensile and micro-hardness tests. Results indicate that changing the route significantly affects the formation of crystallographic texture components in the structure, leading to different macro mechanical properties. As the asymmetry increases in the strain route, the intensity of the texture components reduces by 57% from as-received structure to the most asymmetric ARBed sample, i.e., cross route. The difference is attributed to different activated slip system in each route. The higher the asymmetry of the route, the lesser the necessity for the cross-slip, and the more the dynamic recrystallization in the structure. Hence, the finest grains happen to form in Normal ARBed sample. The same mechanism is responsible for higher strength (36%) and hardness (32%) observed in Normal ARBed sample. However, the change of route also lowers the bond strength in Cross and Reverse ARBed samples, weakening them by almost 12% regarding the as-received sheet.