Microstructure of AZ31 magnesium alloy produced by continuous variable cross-section direct extrusion (CVCDE)

• A new SPD technique-CVCDE for AZ31 magnesium alloy preparation has been presented.
• CVCDE has a greater effect on AZ31 magnesium alloy grain refinement, especially with 2 interim dies.
• Both tensile strength and elongation of CVCDEed AZ31 magnesium alloy are improved.
• Textures have been studied to explain the improved mechanical properties of AZ31 magnesium alloy produced by CVCDE.

In order to study the effect of a new Severe Plastic Deformation (SPD) technique-continuous variable cross-section direct extrusion (CVCDE) on improving the mechanical properties of magnesium alloy, electronic backscattered diffraction (EBSD) was employed to investigate the microstructure and texture of CVCDEed AZ31 magnesium alloy. Compared with conventional extrusion (CE), CVCDE can increase the accumulated strain without changing the total extrusion ratio during extrusion process. Under the effect of CVCDE, coarse grains can be further sheared up to refined grains and the number of dynamic recrystallization grains increases. At the same time, this method can significantly weaken basal plane texture and improve tensile strength and elongation of CVCDEed product, which provides an effective way to produce excellent performance magnesium alloys.