Tailoring the microstructure, mechanical properties, degradation behavior, and biological performance of biodegradable Zn-Cu alloys through plastic deformation processing.

Zn-based alloys have attracted substantial attention as next-generation biodegradable implant materials due to their intrinsic biodegradability, biocompatibility, and unique potential to facilitate tissue regeneration while providing temporary mechanical support. However, systematic studies investigating how different plastic-deformation strategies govern their microstructure and, consequently, their mechanical, corrosion, and biological performance remain scarce. Here, the effects of five plastic-deformation processes, namely, cold rolling, hot rolling, hot extrusion, hot rolling combined with asymmetric rolling, and hot extrusion combined with equal-channel angular pressing (HE+ECAP), on the microstructure, mechanical properties, degradation behavior, hemocompatibility, cytocompatibility, and antibacterial activity of a Zn-3Cu alloy were comprehensively investigated. Microstructural analysis revealed that all processed alloys consisted of an η-Zn matrix and a CuZn5 phase. Notably, the HE+ECAP alloy demonstrated a favorable combination of mechanical, degradation, and antibacterial properties, exhibiting a yield strength of ∼303.4 MPa, ultimate tensile strength of ∼312.4 MPa, elongation of 39.1%, degradation rate of ∼33.4 μm/year after immersion in Hanks' balanced salt solution (HBSS) for 28 days, and inhibition zone diameter of ∼12.8 mm against Staphylococcus aureus. Furthermore, all processed alloys demonstrated satisfying hemocompatibility and cytocompatibility. Overall, HE+ECAP processing synergistically enhanced the comprehensive properties of the Zn-3Cu alloy, advancing its potential for biodegradable orthopedic implants. STATEMENT OF SIGNIFICANCE: This work reports the effects of five plastic-deformation processes, namely, cold rolling (CR), hot rolling (HR), hot extrusion (HE), hot rolling combined with asymmetric rolling (HR+ASR), and hot extrusion combined with equal-channel angular pressing (HE+ECAP), on the microstructure, mechanical properties, degradation behavior, hemocompatibility, cytocompatibility, and antibacterial activity of a Zn-3Cu alloy. The HE+ECAP alloy demonstrated a favorable combination of mechanical, degradation, and antibacterial properties, exhibiting a yield strength of ∼303.4 MPa, elongation of 39.1%, degradation rate of ∼33.4 μm/year, and inhibition zone diameter of ∼12.8 mm against Staphylococcus aureus. All processed alloys demonstrated satisfying hemocompatibility and cytocompatibility. Overall, HE+ECAP synergistically enhanced the comprehensive properties of the Zn-3Cu alloy, advancing its potential for biodegradable orthopedic implants.