Study on the effect of corrosion on the tensile properties of the 1.0 wt.% Yttrium modified AZ91 magnesium alloy

The corrosion residual strength of the 1.0 wt.% Yttrium modified AZ91 magnesium alloy was investigated with the pre-corrosion of the samples in 3.5% NaCl aqueous solution at pH 7.0. In order to analyze the effect of corrosion on the tensile strength, scanning electronic microscope (SEM), optical microscope (OM) and camera were used to record the corrosion morphology and fracture texture. The tensile behavior of test sample was performed on an AG-10TA materials test machine. The results reveal that the initiation and development of corrosion pit, which results in the variation of the surface configuration of the test sample and thus leads to the stress concentration at the corrosion pit, is the main reason for the drop of the corrosion residual strength. The corrosion residual strength closely depends on the dimension of the extreme depth of corrosion pit other than the amount of corrosion pits. The variation of the corrosion residual strength follows the regulation of exponential decay from 0 to 204 h.