An Ultrafine grain (UFG) microstructure is developed on the sheet of Al-2.4wt%Cu-0.3wt%Si alloy after three passes of accumulative roll bonding (ARB) process. The detailed of the microstructural features and phases at different strain condition has been studied by transmission electron microscopy (TEM). Observation indicates at the possibility of dynamic recovery and recrystallisation during the ARB processing itself. The material becomes ultrafine grains after three passes of ARB itself with the formation of dynamically recrystallised grains all over the sample. TEM evidence is presented in support of this proposal.