Mechanical properties of ultrafine-grained pure aluminum by ECAP

Since severe plastic deformation (SPD) was demonstrated as an effective approach to produce ultrafine-grained (UFG) metals over 10 years ago [1,2]. In these techniques, very high plastic strain can be applied to solid bulk materials without any significant changes in the specimen’soverall dimensions. Among different SDP techniques, ECAP has attracted most attention, because it is effective in producing UFG structures having submicron or even nanosized grains [3]. So far the ECAP was used mostly to produce UFG structures in many pure metals, such asCu, Al, Ti and only a few alloys [1,4]. In ECAP process, bulk solid rod or bar is pressed trough a die consisting of two channels having a constant cross section meeting each other at an abrupt bent through a certain angle Φ (usually close to 90o or 120o). This bending angle is an importantparameter in the process. Microstructure and grain size are changed during ECAP as a result of large plastic deformation that takes place in a narrow region at the intersection of two channels [3]. Rotation of billet (processing routes) between passes is another key parameter in ECAPprocess. In general, deformation mechanisms in ECAP depend on material properties andprocessing parameters. For a specific material, number of passes (amount of induced strain), die angle (Φ), and the processing routes are controllable and can widely affect the deformation process and microstructure [5]. In this study CP-Al was subjected to ECAP procedure at room temperature to obtain UFG structure. It is the objective of this study to investigate the effect of ECAP processing routes on the mechanical properties of the CP-Al