NON-BASAL TEXTURES IN MAGNESIUM ALLOY STRIPS PRODUCED BY EXTRUSION- MACHINING

摘要

A constrained chip formation technique, large strain extrusion machining (LSEM), was used to produce bulk magnesium alloy (AZ31B) strips with fine grain size (2-6 μm) and non-basal textures. These characteristics are known to enhance the final formability. The deformation temperature during extrusion-machining was varied by preheating the workpiece to a range of temperatures (50°C to 375°C). Microstructural refinement and texture evolution were studied as function of deformation temperature. It was possible to refine the grain size down to ～2 μm by restricting the dynamic grain growth at low to moderate deformation temperatures (below 320°C). LSEM was shown to be capable of resulting in non-basal textures at low deformation temperatures (below 220°C) as well as at elevated deformation temperatures (above 420°C). The influence of active deformation mechanisms and dynamic recrystallization on the texture development is also addressed.