GENERAL CORROSION AND STRESS CORROSION OF AZ91D IN TWO SALT SOLUTIONS AND AIR

The corrosion test and slow strain rate test of die cast AZ91D magnesium alloy in 060mol/L NaCl and NaNO3 solutions at pH 6 as well as in air were carried out.The selectivity of anions for general corrosion and stress corrosion of AZ91D was obvious.The general corrosion was easier in the presence of Cl-,while the stress corrosion was more severe with the presence of NO-3.Stress corrosion did not occurr in laboratory stationary air.The strain rate was another important parameter for stress corrosion.The stress corrosion of AZ91D took place only when the strain rate was less than 8.33×10-5s-1 in NaNO3 or NaCl solution,and the stress corrosion was the most severe when the strain rate was equal to 4.17×10-5s-1.The stress corrosion was caused by anodic dissolution along with hydrogen embrittlement.