Effect of hierarchical precipitates on corrosion behavior of fine-grain magnesium-gadolinium-silver alloy

An equal channel angular pressing (ECAP) process is used to obtain a fine-grain magnesium-gadolinium-silver alloy, and hierarchical precipitates embedded in the fine-grain matrix are achieved by subsequent peak-aging. These hierarchical precipitates are composed of the beta phase sub-microparticles, beta phase nanoparticles, gamma phase nanoplates, and beta' phase nanoplates. They facilitate corrosion in the 3.5 wt% NaCl solution to some extent due to micro-galvanic corrosion. However, compared to those precipitates in the as-cast alloy, the spatial redistribution of the hierarchical precipitates improves the corrosion resistance of the material, which is possibly attributed to the formation of a protective corrosion product film.

Automated summary

Hierarchical precipitates composed of various phases in a fine-grain magnesium-gadolinium-silver alloy obtained through ECAP and subsequent peak-aging process facilitate corrosion to some extent, but their spatial redistribution improves the material's corrosion resistance possibly due to the formation of a protective corrosion product film.