Synergy of Ni micro-alloying and thermomechanical processing in Al-Mg-Si-Cu-Zn-Fe-Mn alloys with enhanced bendability

Synergy of Ni micro-alloying and thermomechanical processing on the phase distribution, formability and bendability of Al-Mg-Si-Cu-Zn-Fe-Mn alloys was systematically studied in this paper. With the addition of micro-alloying Ni, the Ni-containing Fe-rich phase can be formed, which not only serves as nucleation sites of Mg-Si precipitates (such as, Q phase) during the casting process, but also improves the uniform distribution level of Fe rich phases after homogenization. The formability and bendability of Ni-containing alloy can be both improved to a certain level due to the positive effect of Ni micro-alloying. In comparison, if increasing the cold rolling deformation between hot rolling and annealing, the distribution of multi-scale Fe-rich phases can be significantly improved based on the synergy of Ni micro-alloying and thermomechanical processing. And finally, this improvement further results in the great improvements in the microstructure, texture, formability (average r = 0.688, Delta r = -0.09) and bendability of the alloy together. Based on the microstructure evolution, the synergy mechanism of Ni micro-alloying and thermomechanical processing is put forward in this paper. (C) 2021 The Author(s). Published by Elsevier B.V.