Wettability of molten Sn on AlCoCrCuxFeNi high-entropy alloy

Wettability between the molten Sn and AlCoCrCuxFeNi (x = 0, 0.5, 1, 1.5) high-entropy alloy (HEA) substrates was studied by sessile drop technique at 823 K. The final contact angle decreased with the increase of Cu content in the AlCoCrFeNi HEA. Additional Cu could not only change surface structure of AlCoCrFeNi HEA but also effect on the interfacial reaction between the molten Sn and AlCoCrCuxFeNi HEA. Moreover, with the increasing concentration of Cu, the diffusion of Sn atom along the Cu-rich solid-solution phase in AlCoCrCuxFeNi HEA was much more intense. Accordingly, the enhancement of wetting may be attributed to change of the primary interface reaction product and diffusion of Sn atom along the Cu-rich solid-solution phase.