Evolution of Nanostructure Through Thickness of Deoxidized Low-Phosphorous Copper by Three-Layer Stack Accumulative Roll-Bonding.

A nanostructured deoxidized low-phosphorous copper (DLPC) was fabricated by three-layer stack accumulative roll-bonding process. Three sheets of 1 mm in thickness, 30 mm in width and 300 mm in length were stacked up and roll-bonded to thickness of 1 mm by two-pass cold rolling. The bonded sheet was cut in three pieces of same length, then stacked up and roll-bonded to the thickness of 1 mm again. The evolution of nanostructure through thickness with three-layer stack ARB were investigated in detail. It was found that the microstructure has been evolved from a dislocation cell structure to a nano grained structure with the proceeding of ARB cycles. The average grain thickness of 45 μm in initial decreased to 170 nm after 7 cycles of the ARB. The heterogeneity in microstructure through thickness was also largely decreased by the ARB. These results suggest that three-layer stack ARB is an effective process for a formation of nanostructure of DLPC alloy.