Development of a novel severe plastic deformation method: friction stir equal channel angular pressing

In this research, a novel severe plastic deformation (SPD) method has been proposed which imposes a higher amount of the plastic shear strain during the modified equal channel angular pressing (ECAP) process. The deformation behavior of this novel process was analyzed through the finite element method, and the numerical simulations were validated by experimental data. The results showed that this process can impose higher effective strain during only one pass in comparison with the conventional ECAP even at high numbers of passes. According to the mean stress analyses of the process, it is obtained that this novel method leads to produce products with lower possibility of crack growth in comparison with the common method. At the second pass, the final product of the friction stir equal channel angular pressing (FS-ECAP) process exhibits better strain homogeneity at its surface along the length in comparison with that of the first FS-ECAP pass.