Extrusion techniques on microstructure optimization and quantitative analysis of texture influence on ductility improvement for heat-resistant Mg–Nd–Zn–Zr magnesium alloy

Aiming at the ductility improvement of the rare-earth magnesium alloys, the influence of the microstructure refinement and texture on the strength and ductility was quantitatively analyzed for the Mg–Nd–Zn–Zr alloy subjected to the solid solution and extrusion. At an extrusion temperature of 500–150 °C for the solid-solute rods, abundant dynamic recrystallization and basal texture component change led to the generation of the alloy rods possessing an optimal ductility of 25–40% and a yield strength of 181–250 MPa. During the extrusion process, the <10–10>//ED deformed fiber texture was gradually formed, and the dynamic recrystallization led to a prominent microstructure refinement. The inclined basal texture emerged due to the preferential growth of the recrystallized grains. The yield strength varied significantly with the extrusion techniques, and its relationship with the grain size could be quantified by using the texture, characterized by the initial average equivalent basal Schmid factors $$overline{m}_{{{ ext{bas}}}}$$ , influenced Hall–Petch relationship. The strengthening effect was included by the enhanced value of $$ au_{{0,{ ext{bas}}}}$$ (effective critical resolved shear stress based on basal slip) at yielding and the declined value of $$overline{m}_{{{ ext{bas}}}}$$ from the strain hardening phenomenon during the low temperature extrusion. The high room-temperature ductility of 30–40% was dependent on the refined microstructure and weak inclined basal texture. The promotion of the uniform elongation from the inclined texture had a large contribution in the ductility improvement. This study reveals the regulating effect of the plastic processing on the strength and ductility (especially ductility), along with the importance of texture modification on the properties of the rare-earth heat-resistant magnesium alloys.