Exceptional strengthening in low-alloyed Mg-Zn-Ca-Nd alloy by enhanced dislocation-solute segregation coupling in rotary swaging deformation

Room-temperature rotary swaging (RS) is pivotal for strengthening magnesium alloys. Herein, hot-extruded Mg-1Zn-0.2Ca-0.2Nd (wt.%) alloy achieves exceptional strengthening by tailoring dislocation-solution segregation coupling after 5-pass RS (34% total strain, RS-2 alloy). RS-2 alloy forms an optimized dislocation-segregation-grain boundary configuration, featuring a maximum dislocation density (4.18 × 1014 m−2), prominent Zn (9.3 at.%) /Ca (3.5 at.%) segregation at high-angle grain boundaries (HAGBs) and 32% HAGBs. Its yield strength (315 MPa) and ultimate tensile strength (342 MPa) rise by 64 MPa and 75 MPa, respectively, versus the extruded state. This is attributed to the dual-strengthening effect counteracting the impairment from texture weakening and grain coarsening.