Microstructural evolution and strengthening mechanisms operating during cryogenic rolling of solutionized Al-Cu-Mg alloy

In this work, microstructural evolution of a solutionized Al-Cu-Mg alloy during rolling at liquid-nitrogen temperature was studied and concomitant strengthening effect was elucidated. It was found that a prior solid-solution treatment as well as a lowering of deformation temperature to the cryogenic range essentially suppressed dislocation mobility. This promoted an abrupt increase of dislocation density but considerably retarded microstructural processes, particularly texture evolution and development of deformation-induced boundaries, thus suppressing grain refinement. Hence, the strengthening effect of the cryogenic rolling was mainly contributed by the work hardening mechanism.