Corrosion and tensile behaviors of ultra-fine grained Al–Mn alloy produced by accumulative roll bonding

The corrosion and tensile behaviors of ultra-fine grained (UFG) Al–Mn alloy fabricated by ARB process, and then immersed in 3.5% NaCl artificial seawater for 168 h, were investigated. Compared with coarse-grained (CG) Al alloy, the size and the amount of pitting corrosion in UFG Al sample are decreased. The potentiostatic polarization test shows that corrosion potential of UFG Al alloy is more positive than that of CG polycrystalline, however, the corrosion current density is much lower by ∼33%. After corrosion UFG Al alloy retains nearly unchanged tensile strength, while the degradation of total elongation is significant. Furthermore, the work hardening rate, for both the CG and UFG Al samples, is lower than that of its counterpart respectively. The results indicate that UFG Al–Mn alloy possesses a better corrosion resistance than its CG counterpart; moreover, the effect of environmental corrosion on mechanical behaviors of UFG Al–Mn alloy is pronounced.