HOT WORKABILITY OF ALLOY WE43 EXAMINED USING HOT TORSION TESTING

摘要

While rare earth additions can impart a variety of property improvements in magnesium alloys, they can also limit the processing parameter window inside which the alloys may be successfully wrought in commercial production routes such as extrusion and rolling. In the present work, hot torsion testing is used to explore the temperature and rate sensitivity of the flow stress of the alloy WE43 in order to establish the boundaries of this processing window. Two mechanisms appear to be important from a fundamental perspective: first, dynamic recrystallization appears to be a prerequisite for significant plastic flow; second, serrated flow and negative strain rate sensitivity are observed at lower deformation temperatures (T ≈ 150-250℃). The Sellars-Tegart model and simple power law, both of which have been successfully applied to describe the temperature/strain-rate/flow stress relationship in AZ31 and many other Mg alloys, are explored in the context of WE43.