UFG Al 1070, produced by two-turn, S-channel ECAP, was side upset and rolled to obtain a 1 mm thick sheet. 1mm in diameter cylindrical billets were micro-blanked from the UFG sheet and, for comparison purposes, also from a coarse grained commercially rolled Al 1050 sheet. After calibration the billets were used for backward extrusion of micro-cups. The UFG structure was retained during all these operations, which appeared to be not much different for the two materials. Tooling issues have to be addressed and further investigation is required to account for substantial changes in the strain path for the UFG material.
- backward extrusion
- aluminium sheet