Formation mechanism of <0001> texture connected with excellent ductility during hot extrusion in Mg-9Gd-5Y-0.5Zr alloy

A novel <0001>//ED (<0001>) texture was obtained in Mg-9Gd-5Y-0.5Zr alloy by hot extrusion at 350 °C. The formation mechanism of <0001> texture during extrusion was studied by independent analysis of plastic deformation mechanism, recrystallized (DRXed) behavior, and grain growth. The results showed that the plastic deformation mechanism was dominated by the traditional basal slip, resulting in a strong <10-10>//ED (<10-10>) basal texture at the initial stage of extrusion. The <10-10> texture was gradually weakened by the random nucleation of DRXed behavior dominated by discontinuous dynamic recrystallization (DDRX) and supplemented by continuous dynamic recrystallization (CDRX). Finally, the <0001> texture was formed due to the preferential growth of the low-energy <0001>//ED grains during grain growth process. Compared with the formation of conventional <10-10> texture by hot extrusion in the Mg–Gd series alloys, the formation of the <0001> texture in the as-extruded Mg-9Gd-5Y-0.5Zr alloy achieved outstanding room temperature ductility and hardening ability. The elongation (EL) and uniform elongation (UEL) reached 31.5% and 20.2%, respectively.