Shear texture gradient in AA6061 aluminum alloy processed by accumulative roll bonding with high roll roughness
The through thickness texture gradient in accumulative roll bonding (ARB) processed materials is largely dependent on the friction between the rolls and the sheet during deformation. In this study, AA6061 aluminum alloy was pre-heated to 200 C for 180 s and subjected to ARB deformation under dry conditions for up to 5 cycles using rolls with a high surface roughness. The imposition of high friction conditions during rolling resulted in a large texture gradient in the through thickness of the ARB strip. The bulk texture at the strip surface mainly comprised the Rotated Cube orientation for all cycles. The strip quarter thickness consisted of a combination of a Copper dominated b-fiber and the Rotated Cube orientation after 5 cycles. The bulk texture at the strip center evolved from a predominantly Cube orientation in the fully annealed condition to one that comprised typical fcc rolling orientation components after 1 cycle. Thereafter, a gradual increase in the volume fraction of the Rotated Cube component was seen for up to 5 cycles. As expected, the average bulk texture up to 5 cycles returned the highest volume fraction for the Rotated Cube orientation along with significantly smaller volume fractions for the ideal rolling orientations. The combination of high friction induced shear deformation and the unique alternating sandwich- type deformation pattern of ARB resulted in an increasingly uniform redistribution of shear-type orientation components across the strip thickness with increasing number of cycles.