Effectiveness of Ti micro-alloying for the suppression of Fe impurities in AZ91 Mg alloys and associated corrosion properties

Abstract

In this study, the corrosion properties of Ti micro-alloyed AZ91 Mg alloys, having various Fe impurity contents (0.025 to 0.1 wt..-%), have been investigated. Microstructural investigations were carried out by using scanning electron microscopy. The corrosion behavior of the alloys was evaluated by means of both immersion (3, 7, 21 days) and electrochemical polarization tests in 3.5% NaCl solution. Polarization and long-term immersion tests showed that corrosion resistance was significantly increased by the micro-alloying of AZ91 alloy with Ti, even at very high Fe impurity ratios (i.e, 0.1 wt.-% Fe).