Mechanical properties, dimensional stability, and corrosion behaviour of a low-alloyed Zn-0.22Mn-0.11Cu alloy for biodegradable implant applications

The clinical demand for biodegradable implants has driven the development of zinc-based alloys, which offer more favourable degradation kinetics than magnesium or iron but lack the mechanical integrity required for load-bearing use. This study investigates the microstructural evolution, mechanical performance, dimensional stability, and corrosion behaviour of a low-alloyed Zn-0.22Mn-0.11Cu (wt.%) alloy processed by homogenisation and hot-rolling. Thermomechanical processing refined the as-cast dendritic structure into a highly {0001}-textured matrix with fine, evenly dispersed intermetallic precipitates. The rolled alloy achieved an excellent strength–ductility balance: an ultimate tensile strength of 204.5 ± 10.2 MPa, a yield strength of 163.1 ± 5.8 MPa, and an elongation of 36.3 ± 3.4%. Indentation creep analysis revealed a shift in the dominant deformation mechanism from climb-controlled dislocation creep (n ≈ 4.8) to a power-law breakdown regime (n > 11), markedly improving room-temperature dimensional stability. Rolling also enhanced corrosion resistance in both media, lowering the corrosion current density ≈13-fold in 3.5 wt.% NaCl and ≈2-fold in Hank's solution relative to the homogenised state. These results show that low-alloyed Zn-Mn-Cu systems, optimised through thermomechanical processing, provide the mechanical and creep performance required for temporary orthopedic devices such as bone nails and craniomaxillofacial plates.