Microstructure and mechanical properties of Mg-Nd-Zn-Zr alloy rod prepared by eccentric extrusion

Magnesium (Mg) alloys combining high strength and ductility are in high demand for applications in lightweight structural materials and biodegradable biomaterials. However, conventionally processed Mg alloys often suffer from limited and mutually exclusive strength and ductility. In this study, a novel eccentric extrusion process was developed to fabricate Mg alloy rods with concurrently enhanced strength and ductility. The microstructure and mechanical properties of samples processed by eccentric extrusion (EE) and conventional extrusion (CE) were systematically investigated. The introduction of asymmetrical shear deformation in the EE process significantly intensified dynamic recrystallization and precipitation behavior, leading to finer grains, a weaker texture, and a higher density of secondary phase particles with a narrower size distribution. Consequently, the EE-processed sample exhibited markedly improved mechanical properties compared to the CE-processed counterpart. Specifically, the EE-processed sample exhibited a yield strength of ∼188 MPa and an elongation to fracture of ∼22 %, corresponding to improvements of ∼33 % and ∼22 %, respectively, over the CE-processed counterpart. Mg alloy rods fabricated via the EE process can be further machined into bone screw implants, which are expected to retain the enhanced mechanical properties, thereby enabling broader clinical applications.