Evaluation of the High-Entropy Cr-Fe-Mn-Ni Alloys Compatibility with a Liquid Lead Coolant

The corrosion compatibility of the three newly developed high-entropy alloys of the Cr-Fe-Mn-Ni system with liquid lead coolant has been evaluated at temperatures of 480 °C and 580 °C up to 1000 h exposure. It was established that for all alloys at temperatures up to 480 °C, the main mechanism of the surface layers damage is intergranular corrosion, which consists in etching of the grain boundaries, lead penetration into the matrix and dissolving such elements as Ni, Cr and Mn. When the temperature rises to 580 °C, a combined mechanism of corrosion damage is realized. This mechanism consists in the combination of intergranular corrosion and diffusion of oxygen from the melt into the matrix, which results in internal oxidation of Cr and Mn. The composition of the alloy, which has a minimal corrosion tendency and can be recommended for a usage in contact with a liquid lead up to 500 °C, was established. (author)