Designing Optimal Temperature for Multi-directional Forging Process: A Phase-Field Crystal Study

Abstract:

Using multi-directional forging temperature as the independent variable and adopting the dual-mode phase field crystal model, the nucleation modes, reaction mechanisms, and interactions between grain boundaries and dislocations at different temperatures were investigated. Results show that a mapping relationship between process parameters and grain refinement/coarsening is established, and the optimal processing temperature coefficient is 0.23. Compared with the cases with processing temperature coefficient of 0.19, 0.20, 0.21, 0.25, and 0.27, the refinement effect increases by 256.0%, 146.0%, 113.0%, 6.7%, and 52.4%, respectively. Excessively high temperatures lead to grain coarsening due to dislocation annihilation, and the application of strain can reduce the actual melting point of materials. Even if the processing temperature does not exceed the theoretical melting point, remelting and crystallization may still occur, resulting in an overburning phenomenon that reduces internal defects and increases overall grain size. This research is of great significance for the actual forging process design.