Stress-assisted corrosion behaviour of GH3535 alloy in FLiNaK molten salt environment

Abstract This study investigated the microstructure evolution and corrosion characteristics of GH3535 alloy under working stress in a molten salt environment. Selective diffusion of Cr at the grain boundaries (GBs) of the GH3535 alloy degraded the properties of the GBs, making them preferred locations for corrosion crack invasion. Stress further promoted Cr diffusion and accelerated GB carbide precipitation, thereby forming a corrosion couple between the carbide and matrix that facilitated the expansion of intergranular corrosion cracks into the grains. This study could assist in developing structural materials, such as the GH3535 alloy, that are resistant to molten salt systems for expanded applications.