The influence of strain rate and annealing heat treatments on the corrosion and mechanical properties of WE43 and Zn7Ag biodegradable wires for application in soft tissue reconstructions

This study investigated the influence of annealing heat treatments on the microstructure, corrosion and mechanical behaviour of wires made from the Mg alloy WE43 and the Zn alloy Zn7Ag. The applied strain rate had little influence on the mechanical properties of WE43, whereas decreasing strain rate decreased the strength and increased the ductility of Zn7Ag attributed to creep. The annealing heat treatments had (i) a small influence on the corrosion rate of both WE43 and Zn7Ag wires, (ii) little influence on the mechanical properties of WE43, and (iii) had little influence on the strength of Zn7Ag but tended to decrease ductility and eliminated strain softening. WE43-FA immersed in Zahrina’s interstitial fluid (ZIF) for 12 days had a yield strength that was decreased somewhat but fracture occurred much earlier causing a lower ductility and a lower ultimate tensile strength, attributed to notch sensitivity. Zn7Ag after 12 days and 20 days exposure to ZIF showed some reduction in the yield stress, and also early onset of fracture leading to a large decrease in ductility and some decrease in the ultimate tensile strength, also possibly attributed to notch sensitivity.