Simulation of substructural strengthening in hot flat rolling

Abstract

During the last decade, the mechanism of substructure strengthening has been a research focus. In recent years, some physical models based on three internal state variables: dislocation density, subgrain size and misorientation across subgrain boundaries, have been proposed. To compute the material strength by coupling these physical models with the finite element method (FEM) requires the prediction of the evolution of the above three variables. In this paper, the status of modelling the dislocation substructure evolution by FEM is first reviewed. Problems and difficulties in the simulation are investigated. Various physical models have been incorporated into a commercial FEM program FORGE2 ®. Good agreement is found between the predicted and experimental measured subgrain size. The computed dislocation density and misorientation also show reasonably agreement with the experimental observations. Finally, the material strength is computed by adopting different strengthening models. Further work on the prediction of microstructure for aluminium alloys is discussed.