Tailored heat treated accumulative roll bonded aluminum blanks: failure under bending stresses

Formability of Ultrafine Grained Metals Produced by Severe Plastic Deformation–An Overview

“…The formability in bending and corresponding failure modes have been investigated for AA1050 and AA6016 processed by ARB with some of the results being illustrated in Figure . It shows that the forming forces increase with the number of ARB cycles, which reflects the increasing strength of the material, whereas the bending angle at fracture decrease as compared to the coarse grained state.…”

“…It is also shown that heat treatments can improve the bending formability, which in this case were done using short‐term laser heat treatments in order to spatially limit the effect to the bending line where it is required. With regard to the applicability of failure models for bending of sheets, it was shown that a conventional approach to determine the different stages of damage based on the local variation of strains at the bending edge does provide the correct tendencies for the failure behavior . However, the prediction of the specific states of failure was not valid for ARB processed aluminum alloys .…”

“…With regard to the applicability of failure models for bending of sheets, it was shown that a conventional approach to determine the different stages of damage based on the local variation of strains at the bending edge does provide the correct tendencies for the failure behavior . However, the prediction of the specific states of failure was not valid for ARB processed aluminum alloys . Hence, more work is required to either adapt existing or develop new failure models that can predict damage and failure during bending of UFG metals.…”

“…Even though there are only few experimental results on UFG materials available in literature so far, it seems that heat treatments are generally required to achieve small bending radii . This appears to be a huge limitation, yet, heat treatments prior to bending of sheets are less problematic as compared to other sheet forming processes.…”