Systematic Study of TiC Nanoparticle Effects on the Fatigue Behavior of Zn and Zn Alloys.

Zinc (Zn) is a promising material for biodegradable implants due to its moderate corrosion rate and superior biocompatibility over magnesium (Mg) and iron (Fe). However, its poor fatigue performance limits broader applications. While nanoparticles were discovered to enhance the fatigue performance of metals, the mechanisms remain underexplored. This study investigates nanoparticle-enabled mechanisms for fatigue improvement in Zn. Specifically, the microstructure, tensile, and fatigue performance of pure Zn and Zn nanocomposites containing 1 vol. % and 2 vol. % titanium carbide (TiC) nanoparticles were examined. Results demonstrated that TiC nanoparticles significantly enhanced fatigue resistance of Zn at room temperature (RT) and body temperature (BT). The improved fatigue performance was partly attributed to enhanced tensile strength. Further analysis, including Basquin's equation fitting and fatigue fracture surfaces examination, showed that TiC nanoparticles significantly enhance fatigue resistance by refining grain structure, impeding dislocation movement, altering crack propagation pathways, and promoting energy dissipation during debonding. Moreover, nanoparticle incorporation reduced the temperature sensitivity of Zn's fatigue behavior, ensuring more stable performance under elevated temperatures. Additionally, Zn nanocomposites like Zn-Al-Cu-TiC and Zn- Mg-TiC maintained suitable biocompatibility and corrosion rates. These findings highlight TiC nanoparticles as a powerful solution to overcome Zn's fatigue limitations for biodegradable medical devices.