Equal-channel angular extrusion is an innovative forming process to extrude material without substantial change in its geometric shape. Multiple extrusions from equal-channel angular extrusion allows heavy plastic strain to the bulk material. More importantly, by changing the orientation of the billet between successive extrusions, sophisticated microstructures and textures can be developed in the material. According to the orientation chosen after each pass, four fundamental equal-channel angular extrusion routes (A, B, C, and C´) are defined and used for different purposes. It is important to understand the flow pattern after each route because it significantly impacts the formation and orientation of the microstructures. this article, we establish a three-dimensional computational model to predict the flow pattern. To this end, a unified mathematical description for all equal-channel angular extrusion routes will first be given. After that, we construct the self-consistent velocity field for equal-channel angular extrusion. Based on the results from numerical calculation, the flow pattern can be graphically simulated for any route and pass number.

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SOURCE: Cui H. J., R.E. Goforth and K. T. Hartwig. "The Three-Dimensional Simulation of Flow Pattern in Equal-Channel Angular Extrusion". JOM-e, Vol. 50, No. 8, TMS, August 1998.