Characteristics of Nano Grained AA1050/AA5052 Al Sheets Fabricated by Accumulative Roll-Bonding.

Accumulative roll-bonding (ARB) is the most appropriate process for sheet-shaped materials because it can be carried out readily by utilizing the conventional rolling apparatus. In this study, a nanostructured AA1050/AA5052 Al alloy sheet was successfully fabricated by four-layer stack ARB process. The ARB of AA1050 and AA5052 alloy sheets was performed up to 6 cycles without a lubricant at ambient temperature. The sample fabricated by the ARB was a multi-layer aluminum alloy sheet in which AA1050 and AA5052 layers are alternately stacked. The layer thickness of the each alloy became thinner and elongated to the rolling direction with the number of ARB cycles. The grain size decreased with increasing of the number of ARB cycles, after 6 cycles it became about 180 nm in thickness. The fraction of high angle grain boundaries increased with the number of ARB cycles. The tensile strength also increased with the ARB, it reached 305 MPa which is about 2.1 times that of the as-received AA1050. The mechanical properties of a multi-layer AA1050/AA5052 alloy fabricated by the ARB were compared to those of the other materials.