Hot deformation behavior, microstructure evolution and slip system of Mg-2Zn-0.5Mn-0.2Ca alloy

The hot deformation behavior of as-cast Mg-2Zn-0.5Mn-0.2Ca alloys was investigated by hot compression tests conducted at 250-400 degrees C with strain rates of 0.001-1 s(-1). The true stressestrain curves showed that flow stress increased with the increase of strain rates and decrease of temperatures. The constitutive equation was obtained, and the calculated average activation energy is 196.79 kJ mol(-1). The processing map is developed. Combined with the analyses of microstructural and processing map, the optimal processing parameter is determined at 350 degrees C and 0.001-0.1 s(-1). Based on EBSD analysis, the microstructures of the instability areas and the stable areas are quite different, yet both have a < 0001 >//CD texture. The slip system in deformed grains was determined by the in-grain misorientation axis (IGMA) analysis. Typical discontinuous dynamic recrystallization (DDRX) mechanism is the main dynamic recrystallization (DRX) mechanism. As the decrease of the strain rates and the increase of the deformation temperatures, the DRX fraction gradually increased, meanwhile, the behavior of DRX has an obvious weakening effect on texture strength. (c) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

The hot deformation behavior of as-cast Mg-2Zn-0.5Mn-0.2Ca alloys was investigated by hot compression tests. The flow stress was found to increase with higher strain rates and lower temperatures. A constitutive equation was obtained, and the average activation energy was calculated. A processing map was developed, and the optimal processing parameters were determined. The microstructural analysis revealed significant differences between instability areas and stable areas, although both had a similar texture. The slip system in deformed grains was determined, and the main dynamic recrystallization mechanism was identified as discontinuous dynamic recrystallization (DDRX). The proportion of DRX increased with lower strain rates and higher deformation temperatures, weakening the texture strength.