Double-billet incremental ECAP

Batch SPD processes have a limited scope for being used on an industrial scale. More feasible are continuous processes among which the new SPD process of Incremental ECAP (IECAP) is an attractive option. In this paper, a double-billet version of I-ECAP, which doubles process productivity, is presented. The concept of the process is first checked using the finite element (FE) method. FE simulation results are the basis for the design of an experimental rig. Trials of nanostructuring of 10x10x200 Al 1070 billets are carried out with the forces on the reciprocating die and the feeder measured. Metallurgical samples after 4 and 8 passes of I-ECAP (route BC) are investigated using TEM. Tensile properties after 8 passes are established. All these results show that the new SPD process of I-ECAP gives the results comparable to those obtained by a classical batch ECAP with the added capability of dealing with much longer (possibly infinite) billets.