On the feasibility of using a continuous processing technique incorporating a limited strain imposed by ECAP

Equal-channel angular pressing (ECAP) is used extensively in many laboratories for the production of metallic alloys having grain sizes in the submicrometer or nanometer range. However, the ECAP process is discontinuous and it is not easily adopted for use in commercial forming operations. Attempts have been made to overcome this limitation by incorporating a single ECAP step, equivalent to an imposed strain of ∼1, into continuous production runs based primarily on alternative industrial procedures such as rolling. Experiments on commercial-purity aluminum and a series of Al-Mg solid solution alloys show this is a feasible approach because very significant strengthening is introduced into bulk solids in the first pass, often leading to an increase in strength by a factor of about 2. However, these low strains are not sufficient to produce materials suitable for use in superplastic forming operations.