Chemical compatibility of high entropy alloys with liquid PbLi

The chemical compatibility and corrosion resistance of three different high entropy alloys of CrFeV-X, where X = CuW, CuMo, TaW, to stagnant eutectic PbLi was studied. Three nominal HEAs compositions, Cr35Fe35V20W5Ta5 (H-TaW), Cu5Cr35Fe35V20W5 (H-CuW) and Cu5Cr35Fe35V20Mo5 (H-CuMo) were prepared by vacuum arc melting under a low pressure He atmosphere using a non-consumable W electrode and starting from pure elemental pieces with purity > 99.97. Planoparallel specimens of the HEAs were mirror polished and subjected to stagnant PbLi at the eutectic composition, (14.9 ± 1.99) % of Li, at a temperature of 550 °C, corresponding to the working temperature of the WCLL, for increasing times of 168 and 1344 h. After the tests, the microstructure of the samples was cleaned to remove adhered PbLi and analyzed by SEM/EDX and EBSD. SIMS measurements were performed to study the diffusion of into the matrix. From the concentration curves of lithium in the alloys, the diffusion differences of lithium were determined and correlated with the differences in the alloying elements. Furthermore, the corrosion behavior of the alloy showed important differences with the composition of the HEAs and their differences in microstructure. The most significant result is that W has a detrimental effect on the corrosion resistance of PbLi.