Corrosion Behavior of AZ31 Magnesium Alloy with Different Grain Sizes

AZ31 magnesium alloy is attractive as a candidate for biodegradable implanting devices. Depending on the actual applications, it is often necessary to modify the microstructure of materials to achieve different properties. It is critical to understand the relationship between microstructure and corrosion property of AZ31 magnesium alloy. This work focused on the effect of grain size on corrosion behavior of AZ31 magnesium alloy. Heat treatment was employed to obtain the samples with different grain sizes. Bio-corrosion test was conducted for the samples through being immersed in simulated body fluid for various time intervals. Scanning electron microscope was employed for observing morphology changes due to corrosion testing. The results show that the corrosion rates increased with the immersion duration for the samples, the samples with larger grain size exhibited better corrosion resistance, and the corrosion mechanisms for the sample was uniformly pitting corrosion.