Modelling Microstructure Evolution in Polycrystalline Aluminium – Comparison between One- and Multi-Parameter Models with Experiment

Abstract

The plastic response of an aluminium alloy type A6061 is modelled using different state parameter‐based approaches. Several of these models (one‐ and two‐parameter models) have recently been implemented into the thermo‐kinetic software package MatCalc. In the present work, a model based on the Kocks-Mecking-law is used to investigate the capabilities of one and two parameter approaches in order to model experimental data. The experimental work presented here is performed on a Gleeble 1500 thermo‐mechanical simulator for different natural ageing times. We demonstrate that one‐parameter models offer a ready‐to‐use and easy‐to‐calibrate solution for a rough correlation between flow‐curve data and microstructure. Such models describe the evolution of the average dislocation density in time. In many practical cases, a single state parameter is insufficient and multi‐parameter models must be utilized, for instance, with consideration of separate populations of dislocations in walls and subgrain interior. These approaches can consistently represent the deformation behaviour of alloys in a variety of conditions with respect to temperature and strain rates.