What is it about?
In this manuscript, we investigate the influence of hydrogen on the environmentally assisted cracking of the high-strength magnesium alloy AZ31B.
Why is it important?
Based on the reversibility of the pre-exposure embrittlement effect, we were able to demonstrate that the AZ31B alloy was, indeed, susceptible to internal hydrogen embrittlement. The width of the annular brittle region observed in post-exposure fractography, doubled with a fourfold increase in pre-exposure time, suggesting that hydrogen diffusion controlled pre-exposure embrittlement. Similarly, pre-corroded tensile samples of AZ31B Mg alloy showed a decrease in ductility and UTS that was a function of the pre-exposure time. In all cases, the loss of ductility, which was not influenced by chloride concentration, was partly recovered by exposure to dry air. Moreover, results conclusively showed that anodic processes were not rate-controlling. It is plausible to assume that other high-strength magnesium alloys could exhibit a similar behavior.