Corrosion and corrosion-erosion behaviors of FeNiCrAl high-entropy alloys with minor alloying elements in lead-bismuth eutectic

The corrosion and corrosion-erosion behaviors of FeNiCrAl high-entropy alloys (HEAs) incorporating Si and Nb/Ti were investigated in lead-bismuth eutectic (LBE). The introduction of alloying elements markedly enhances corrosion resistance, wherein Si may retard oxidation kinetics, and Nb/Ti are potentially associated with the formation of Cr-rich and Al-rich oxides, respectively. Corrosion-erosion testing conducted in dynamic LBE at a relative velocity of 4 m/s reveals a clear order in corrosion-erosion resistance, with the Si-containing HEA exhibiting the highest performance, followed by the Nb/Ti-containing HEA, and the original HEA showing the lowest. The additions of alloying elements reinforce the protective ability of the oxide layer, with Si may playing a particularly critical role in improving oxide layer adhesion to the matrix. Corrosion-erosion morphologies vary considerably across regions of different impact angles, largely governed by the stress distribution induced by the flowing LBE.