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

Abstract

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 degrees 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 degrees C. Microstructural studies showed that the beta (Mg17Al12) intermetallic phases in the AZ31 alloy are dispersed in the microstructure and formed as relatively angular particles, and that the dimensions of the beta 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.