In this work, a systematic analysis of the hot deformation mechanism and a microstructure characterization of an as-cast single α-phase Mg-4.5 Li-1.5 Al alloy modified with 0.2% TiB addition, as a grain refiner, is presented. The optimized constitutive model and hot working terms of the Mg-Li alloy were also determined. The hot compression procedure of the Mg-4.5 Li-1.5 Al + 0.2 TiB alloy was performed using a DIL 805 A/D dilatometer at deformation temperatures from 250 °C to 400 °C and with strain rates of 0.01-1 s-1. The processing map adapted from a dynamic material model (DMM) of the as-cast alloy was developed through the superposition of the established instability map and power dissipation map. By considering the processing maps and microstructure characteristics, the processing window for the Mg-Li alloy were determined to be at the deformation temperature of 590 K-670 K and with a strain rate range of 0.01-0.02 s-1.
Keywords: constitutive model; flow stress; hot compression test; magnesium alloy; microstructure evolution; processing map.