Fatigue-induced microstructure evolution and ratcheting behavior of ultrafine-grained (UFG) pure aluminum processed by accumulative roll bonding (ARB)

In the present work, fatigue and cyclic deformation behavior of ultrafine-grained (UFG) pure aluminum AA1100 product by accumulative roll bonding (ARB) process under stress-controlled in the presence of mean stress were performed. After seven cycles of the ARB process, grain refinement due to severe strain imposed improves tensile properties. The fatigue life shows a substantial reliance on the ARB cycle, so that the fatigue life improves with the increasing ARB cycle. Fatigue-induced microstructural evolution was investigated by TEM microscopy. Cyclic deformation behavior in the presence of mean stress leads to strain accumulation in each cycle. The amount of strain accumulated increases by increasing mean stress and stress amplitude. TEM observations demonstrated that dense dislocation patterns such as dislocation tangle and LAGBs were recovered and turned into HAGBs during cyclic deformation.

Automated summary

In this study, the fatigue and cyclic deformation behavior of ultrafine-grained pure aluminum AA1100 product by accumulative roll bonding (ARB) process under stress-controlled in the presence of mean stress were investigated. The tensile properties of the material were improved due to grain refinement caused by severe strain imposed during seven cycles of the ARB process. The fatigue life was found to depend greatly on the ARB cycle, showing an increase with the increasing cycle. TEM observations revealed the microstructural evolution induced by fatigue, with dense dislocation patterns recovering and transforming during cyclic deformation.