Development of extrusion-torsion simultaneous processing for grain refinement in Magnesium alloys

We have proposed a new extrusion process combined with torsion. Extrusion-torsion simultaneous processing is a very attractive technique for fabricating a rod-shape material with high strength and excellent workability. The grain size of AZ91D magnesium alloy was gradually decreased with increasing the torsion speed in as extrusion-twisted conditions. Grain refinement under 2um was achieved by the optimized extrusion-torsion condition. Hardness was increased by the addition of torsion speed comparing with as solution-treated and as extruded samples. Hardness change was dependent on the extrusion-torsion temperature.