Effect of Adding Rare Earth Elements Er and Gd on the Corrosion Residual Strength of Magnesium Alloy

Abstract

Abstract The effects of the single and compound addition of rare earth Gd and Er on corrosion resistance and residual strength of as-cast AM50 magnesium alloy were studied using XRD, SEM, EDS, the weightlessness test, electrochemistry method, and tensile test. The results of XRD and SEM showed that Al3Er, Al2Gd3, and Al–Mn–Gd(Er) phases appeared in the alloy structure after the addition of rare earth Er and Gd. The results from the weightlessness test and Tafel curves show that the corrosion resistance of the modified composite rare earth was improved. Stress concentration caused by a corrosion pit is the direct cause of the tensile samples after corrosion. The corrosion residual strength of modified composite rare earth specimens is better than that of modified single rare earth samples. Fracture analysis indicates that the addition of rare earth elements did not change the fracture mechanism of the alloy, and the fracture was still the cleavage fracture.