Shear Strain Distribution in Cylindrical Samples Subjected to Deformation by Various Routes of Equal Channel Angular Pressing

Equal-channel angular pressing (ECAP) is an efficient process to produce bulk nanostructured materials, in which a large amount of strain can be imposed on the workpiece via multiple passing deformations without changing its dimensions. In this study the distribution of induced strain was analytically modeled by correlating the Cartesian coordinates with inclination angle (α) and polar angle (θ). The effects of die angles and the routes A and B (without and with rotation 90◦ around the billet axis) were evaluated. The results indicated that the degree of strain rate for the inner corner was three times higher than that of the outer corner. In deformation via route A, the degree of strain rate for θ changed from pass to pass, but for α was the same for all the applied passes. In comparison, when the sample was subjected to deformation through route B, the strain distribution patterns altered from pass to pass. For route B, the maximum value of the inhomogeneity index was approximately 1.5 times less than that of route A.