Stress Corrosion Behavior of Gadolimium Modified Magnesium Alloys in Solution

AM50 magnesium alloy was modified by adding rare earth element Gd with mass fraction of 0.5%，1%，1.5% and 2%. The stress corrosion behavior of these samples in air，deionized water and NaCl solution was studied by an optical microscope，X-ray diffraction，a scanning electron microscope and corrosion slow strain rate tensile test. The results show that the white granular intermetallic compound Al2Gd appears in the alloy structure after Gd addition. With the increase of Gd addition，the quantity and volume of Al2Gd increase while the β-Mg17Al12 decrease. The slow tensile test results show that the anti-stress corrosion sensitivity increases with the addition of Gd in deionized water. In NaCl solution，the AM50+0.5%Gd Mg alloy shows the best stress corrosion resistance. In addition，Gd addition does not change the fracture mechanism of the alloy，which is still quasi cleavage fracture. Under stress conditions，the pitting and development caused by corrosion is the direct reason for the decrease of the ultimate tensile strength. With the addition of Gd，the change of specimen morphology caused by film fracture mechanism in the process of specimen fracture is the main reason for samples’failure. © 2024 Editorial Office of Chinese Rare Earths. All rights reserved.