Microstructural modelling of aluminium alloys during thermomechanical processing

Abstract

It is well-accepted that modelling of microstructural evolution of aluminium alloys during thermomechanical processing is highly desirable to predict product properties and/or to design process variables based on requirements for the properties. To do so, having soundly based physical models is of interest for both academic research and industrial practice. In the present paper, models for predicting the evolution of internal state variables such as internal dislocation density, subgrain size and misorientation between subgrains, and subsequent recrystallisation behaviour are developed for both constant and transient deformation conditions. In predicting the evolution of the internal state variables under transient deformation conditions, the internal 'geometrically necessary' dislocation density is related to the subgrain boundary dislocation density. In the model to predict static recrystallisation behaviour, nucleation of recrystallisation is initially discussed based on experimental results and quantitative metallographic observations. In the calculation of recrystallisation nucleation density, distribution of subgrain size and misorientation between subgrains are key parameters. The predicted evolution of internal state variables and subsequent recrystallisation kinetics and recrystallised grain size using the developed model are in reasonable agreement with experimental data. © 2000 Elsevier Science S.A.