IMPROVING THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF MAGNESIUM-ALLOY SHEETS WITH A NEW EXTRUSION METHOD

A new effective extrusion technique, including integrated direct extrusion and bending-shear deformation, was proposed to fabricate AZ31-magnesium-alloy sheets with high performance, and the grain refinement, texture and mechanical properties were further investigated. The results show that the new extrusion technique can noticeably refine the grain size from 240 mu m to 3.2 mu m at 563 K, and the basal texture is also dramatically weakened, which can be attributed to a fully dynamic recrystallization triggered by a large shearing strain accumulated due to a bar-sheet deformation and continuous bending-shear deformation. Consequently, the ductility significantly increases from 11.67% to 27.7%, and the ultimate tensile stress can still keep a high value of 290 MPa, rendering this new technique an effective processing method for further tailoring of the microstructure and properties of Mg-based alloys for a wide range of engineering applications.