Fabrication of ultratine grained aluminum by differential speed accumulative roll-bonding (ARB) process

The differential speed accumulative roll bonding (DSARB) process was attempted to strengthen 1100 aluminum sheet via grain refinement. The roll peripheral speed of one roll was 2.0 m/min and that of another roll was 3.6 m/min. The roll speed ratio was kept at 1.8. The accumulative roll bonding was conducted up to 6 cycles at ambient temperature without lubrication. For comparison, the conventional accumulative roll bonding (CARB) process was conducted with a rolling speed of 3.0 m/min. The grains developed by the DSARB process were more equiaxed than those produced by the CARB. Tensile strength of the DSARB processed sample was higher than that of the CARB processed sample at the same plane strain compressive strain. The elongation was not affected significantly by the number of ARB cycles. The DSARB process was more effective for grain refinement and strengthening than the CARB process.