Background: The hot working characteristic of magnesium alloys have received considerable
attention in order to evaluate the constitutive behavior of these alloys under hot working conditions
with a view to evaluate constitutive conditions to optimize hot workability and control the microstructure
so as to obtain consistent mechanical properties.
Methods: The hot deformation response of a new dilute Mg alloy was investigated by means of a series
of hot compression tests in the temperature and strain rate range of 375-450°C and 0.001-1 s-1,
respectively. The stress-strain behavior, microstructure evolution and processing parameters optimization
were studied carefully. Micro-structural characterization studies conducted on a series of deformed
samples using optical microscopy revealed that during hot deformation, the main restoration
mechanism was dynamic recrystallization (DRX).
Results: In the final microstructure of the material, grain boundaries were thoroughly covered by
layers of fine DRXed grains. Moreover, a strong twinning induced necklace structure was the most
significant characteristic at high strain rates which was accompanied by smaller grain size in the domain
material. Based on the measured stress-strain data, constitutive model was conducted on two
regimes of low and high temperatures. Moreover, the processing map of the studied material was obtained
and interpreted using dynamic material model (DMM).
Conclusion: The processing map was built and divided into a feasible domain at high temperatures
in the whole range of strain rates and two separated instable domains in the temperature range of 375
to 435°C at high and low strain rates of 1 and 0.001 s-1.