Evolution of microstructure and texture for an Al-0.4 Er alloy during accumulative roll bonding

Abstract

Accumulative roll bonding (ARB) (comprising repetitive cycles of rolling) is highly attractive for the production of metal sheets with an ultrafine grained microstructure. The evolution of the microstructure and texture was investigated using optical microscopy, transmission electron microscopy and electron backscattered diffractometry during four cycles of ARB applied to an Al-0.4 Er alloy. Dynamicly recrystallized grains and deformed grains coexisted after the initial ARB cycle. The Er restricted abnormal grain growth, and facilitated the formation of a finer microstructure. Increasing number of ARB cycles caused a smaller grain size and a greater fraction of high angle grain boundaries. The mechanism was: (i) ARB caused a more uniform distribution of shear strain and a more remarkable texture evolution, and (ii) Er inhibited the texture intensity, and improved the random texture component.