| Modeling the effect of backpressure on dislocation cell structure during simple shear extrusion |
| Paper ID : 1140-UFGNSM-FULL |
| Authors: |
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Hassan Sheikh *1, Ramin Ebrahimi2 1SHAHIN-SHAHR 2Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, Iran |
| Abstract: |
| The mathematical modeling the microstructural evolution during severe plastic deformation can aid to design the SPD process. In this study, the effect of backpressure on the microstructure evolution is modeled for a new severe plastic deformation introduced as simple shear extrusion (SSE) process. The evolution of microstructure is predicted by a dislocation density-based constitutive model named as ETMB model (Estrin, Toth, Molinari, and Brechet) in which the effect of strain reversal is considered. This dislocation-based model is embedded in a crystal plasticity finite element (CPFE) model for commercial purity copper. In the FE model, a polycrystalline aggregate at the central region of the billet is subjected to deformation history experienced by the SSE process. Using the modified ETMB model, the predicted results show that the cell size after a complete pass of SSE process without backpressure is less than that of with backpressure one and this is vice versa for dislocation densities. These results indicate that straining through the second half of die channel and backpressure retard grain refinement during the SSE process. |
| Keywords: |
| Simple shear extrusion (SSE), Backpressure, Dislocations density, Cell size, Crystal plasticity, Finite element |
| Status : Paper Accepted (Poster Presentation) |
