Excellent strength-ductility balance of fully recrystallized fine-grained Mg-Y-Zn-Ni extrusion alloy with 14H-LPSO lamellas

Simultaneously improving strength and ductility is a challenge for Mg alloys. Herein, we report a strong and ductile Mg90Y4Zn2Ni4 (at. %) extrusion alloy with yield strength of 426 MPa, ultimate tensile strength of 451 MPa and elongation of 25%. Experiment and phase field model show that 14H-LPSO phases refine from blocks to lamellas through cracking, dissolving and kinking during deformation. Moreover, excellent strength-ductility balance is attributed to fully and fine recrystallized grains, dispersed Mg(Ni, Zn)4Y particles and 14H-LPSO lamellas, high-density dislocations and easy mobility of basal slip. These findings provide a valuable reference for preparing high-performance Mg alloys.