Coupling of Bezier-type streamline and ETMB model to predict dislocation cell size in ECAE

Abstract

In this research, the generalized streamline introduced by previous researchers based on the Bezier geometrical method for a rectangular cross section of equal channel angular extrusion (ECAE) was applied to predict the dislocation cell size distribution. For this purpose, the Estrin-Toth-Molinari-Brechet (ETMB) model was coupled to the kinematically admissible strain field obtained by the Bezier geometrical modeling. In contrast with many analytical methods, using this approach, a non-uniform strain distribution was obtained in the deformation zone, which is in good agreement with the results of numerical methods such as finite element (FE) simulation. Results showed that by decreasing the inner angle, the strain is increased in ECAE. Therefore, the evolution of the dislocation cells in the inner angle of the die was more pronounced than in the outer angle of the ECAE die. The effect of the outer corner angle was investigated and it was found that with increasing the outer curvature a non-uniform dislocation cell size is achieved.