Microstructure and Mechanical Properties of Layered Aluminum Alloy Sheets Fabricated by Multi-Stack ARB Process

A layered Al sheet was fabricated by three cycles (c) of multi-stack accumulative roll-bonding (ARB) using commercial AA1050, AA5052, and AA6061 alloy sheets, and then annealed. The as-ARBed Al sheet showed ultrafine grained (UFG) structure, with average grain diameter of 1.07 μm. Through up to 250℃, the annealed sheets still showed UFG structure, above 300℃, they exhibited heterogeneous structure, in which due to static recrystallization, both ultrafine and coarse grains coexisted. As the number of ARB cycles increased, the tensile strength increased, after 3c, they reached 390 MPa, 2.4 times the average value of the starting materials. The changes in microstructure and mechanical properties of the multi-layered Al sheet with annealing are discussed in detail, and compared to those of the 2c ARBed materials by the previous study.