Quantification of strain in accumulative roll-bonding under unlubricated condition by finite element analysis

The each strain component and equivalent strain in rolled materials were quantified using finite element analysis (FEA) that takes the deformation history into account. FE simulations were carried out considering stress-strain relations that depend on strain rate and friction between rolls and sheet. Rolling condition of accumulative roll-bonding (ARB) where introduction of a very large shear strain in the surface layer of rolled sheet had been verified through the embedded-pin method was employed in FEA. The histories of total shear strain, total strain in rolling direction, and equivalent strain during rolling were studied, and the magnitude and distribution of each of them through sheet thickness after rolling were shown. The problems associated with the experimental determination from an embedded-pin method were clarified through the present analysis. The equivalent strain at the surface in the 1100 Al processed by one ARB cycle without lubricant corresponded to the equivalent strain in the material processed by five ARB cycles with lubricant. These quantitative strain analyses would be useful for analyzing the evolution of microstructures in the ARB process as well as the conventional rolling deformation under high friction conditions.