Application of a dislocation model for FE-process simulation

Modelling of microstructure evolution during hot rolling of AA5083 using an internal state variable approach integrated into an FE model

“…This was done using a hyperbolic sine equation, shown in Eq. (11), which relates the steady state flow stress of the material to the strain rate and temperature under which it is deformed [15]:…”

“…Although modelling can be a useful tool for understanding microstructure evolution, to date, only a few mathematical models have been developed to predict the microstructure evolution in aluminum alloys during hot rolling [3,[6][7][8][9][10][11]. The main difficulty in developing a fundamentally based model to quantify the effect of hot rolling parameters on the microstructure evolution stems from the fact that the effect of the rolling process parameters on the deformed microstructure and subsequent recrystallization process is not well understood.…”

Modelling flow stress behaviour of aluminium alloys during hot rolling

“…For aluminium alloys, it has been reported that at low strains this equation gives good consistency with experimental data, however, at high strains, it deviates from experimental results. 5,8 In order to modify this model a two variable model has been proposed to determine the dislocation density and flow stress of aluminium alloys. The model is based on two independent variables, F51/bL where L is dislocation mean free pass, and r the density of dislocations.…”

The Coupled Model of a Microstructure Evolution and a Flow Stress Based on the Dislocation Theory

“…To obtain a current value of an average dislocation density r av it is utilized the relation (3) for the dislocation density r of a non-recrystallized grain and the recrystallized fraction c according to (12): That relation is like the other equations that are used for the calculation of other parameters during the recrystallization, for example for the flow stress. In the model the dislocation density is calculated at first and the flow stress (1) then.…”

“…10) They used the dislocation density as the only parameter. To reckon the recrystallization there have been proposed models with two, 11) three 12) internal variables or the dislocation density distribution function. 13) Those models, however, consider the recrystallization implicitly.…”