In Vitro Degradation Behavior of Ti-Microalloyed AZ31 Magnesium Alloy in Simulated Body Fluid

Corrosion and corrosion-related mechanical behaviors of Ti-microalloyed AZ31 Mg alloy (AZ31Ti) in simulated body fluid (SBF) under a dynamic environment were investigated. AZ31 Mg alloy was used as a control alloy. Microstructure analysis of the samples was performed by using a scanning electron microscope and an x-ray diffractometer. Mass loss measurements and corrosion-related tensile tests were carried out by immersing the samples in the SBF solution at 37.5±0.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$37.5 \pm 0.5$$\end{document} °C for 24, 72, and 336 h under dynamic conditions. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were also employed in the SBF solution at 37.5±0.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$37.5 \pm 0.5$$\end{document} °C. Microstructural studies showed that the β (Mg17Al12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{Mg}}_{17} {\text{Al}}_{12}$$\end{document}) intermetallic phases in the AZ31 alloy are dispersed in the microstructure and formed as relatively angular particles, and that the dimensions of the β phases transformed to a smaller size and globular form with Ti microalloying. While the tensile strength and hardness values of AZ31 and AZ31Ti alloys were similar to each other, Ti microalloying showed a considerable increase in the yield strength and elongation. This study suggests that microalloying of AZ31 alloy with Ti is beneficial in terms of their corrosion resistance and corrosion-related mechanical properties in an SBF environment under dynamic conditions.