Effect of geometric parameters on strain, strain inhomogeneity and peak pressure in equal channel angular pressing – A study based on 3D finite element analysis

Equal channel angular pressing (ECAP) is currently being widely investigated because of its potential to produce ultra-fine grained microstructures in metals and alloys. Considerable research has been reported on finite element analysis (FEA) of this process, assuming 2D plane strain condition. The 2D models do not give details of strain distribution in the work-piece. Reports of all the researches are on effect of one-parameter-at-a-time. Combined effect of all geometric parameters is not reported. This paper aims in fulfilling the gap. In the present work 3D FEA of ECAP process was carried out for different combinations of channel angle, inner and outer corner radii. Results in terms of peak pressure, strain and strain inhomogeneity were obtained and analyzed by analysis of mean (ANOM). Main effects and interaction effect of all geometric parameters were quantified by analysis of variance (ANOVA). From the analysis it was found that the peak pressure is largely influenced by channel angle. To obtain desired strain the most important factors are channel angle and outer corner radius. Outer corner radius has the largest influence followed by channel angle on the strain inhomogeneity. There exists an optimum outer corner for which strain inhomogeneity is minimum, which depends on the channel angle. Inner corner alone has no influence on the strain inhomogeneity but its interaction with channel angle has some influence.