Deformation behaviour and microstructure development of Twin Roll Cast AZ31 strips

  • M. Ullmann
  • R. Kawalla
  • H.-P. Vogt


The new energy efficient method of producing magnesium strips down to 1,0 mm thickness based on Twin
Roll Casting (TRC) and Strip Rolling in industrial scale developed at the Institute of Metal Forming at the TU
Bergakademie Freiberg in cooperation with the MgF Magnesium Flachprodukte GmbH Freiberg (Germany) is
described. The design of rolling schedule was analyzed, based on the control of the recrystallization behaviour,
to achieve fine grain in the strip rolling process of the magnesium alloy AZ31. The dynamic recrystallization
behaviour of this alloy during hot deformation was determined with help of plane strain compression tests and
microscopic examination. The influence of temperature, strain and strain rate on the activation of dynamic
recrystallization process during deformation was analyzed. The deformation behaviour was also simulated with
semi-empirical models including specific coefficients related to processing parameters (strain, strain rate and
temperature). The results show that the grain size of this alloy refine steadily with increasing rolling passes by
dynamic recrystallization. The tensile strength and ductility were improved correspondingly.