Study of grain orientation effect on the corrosion behavior of biocompatible magnesium alloy Mg–2Zn-0.5Ca

In recent years, biocompatible magnesium alloys have garnered extensive attentions because of their wide applications in clinical medicine. Their excellent biocompatibility allows the avoidance of secondary surgeries for removal. However, magnesium-based biocompatible alloys are still suffering from some shortcomings such as rapid corrosion rate, causing limited service time. Among the factors that influence the corrosion resistance, the grain orientation (GO) is a primary factor influencing its corrosion behavior. Since the surface energy differs among various grains with different orientations, the corrosion sensitivity is anisotropic. Based on the 10T samples, we have established a functional relationship between the reciprocal of corrosion rate and the percentage of each grain orientation. The fitting parameters for the grain orientations of (0001), (1–100), and (11–20) are 0.133, 0.034, and −0.0287, respectively. This intuitively demonstrates that different grain orientations exhibit varying sensitivity to corrosion, with (0001) showing the highest corrosion resistance, while (11–20) has a negative impact on improving corrosion resistance. Furthermore, when we applied this formula to another set of 3T samples, we found that the calculated results matched well with the actual measurements, indicating that this formula has a certain degree of accuracy in quantifying the relationship between corrosion rate and grain orientation.

(3T and 10T represent for the annealing treatment made at 400 °C for 3 and 10 min respectively.)