Hot workability and extrusion modelling of magnesium alloys

The hot working of commercial Mg alloys differs from creep in so far that twinning is much more prevalent in the early stages and dynamic recrystallization (DRX) becomes extensive above 400 °C. Subgrains form mainly near the grain boundaries and have similar dependence on stress; they were larger in hot working tests because of the much higher temperatures. Extrusion is ideal for breaking down the cast structure as a result of the high compressive mode to minimize cracking at segregated particles and to create a deformation zone reaching near 500 °C to ensure DRX for grain refinement. The constitutive equations and microstructures from torsion testing can be utilized in modeling to guide optimization of extrusion processing.