Solute segregation-induced high-temperature oxidation behavior of Cu-Ni-Sn alloy via experimental and thermodynamic investigations

Segregation-induced oxidation of Cu-15Ni-8Sn (wt%) alloy at 850 °C was studied by CALPHAD_based modeling and key experimental characterizations. In this work, the comparative oxidation of as-cast, homogenized and aged Cu-15Ni-8Sn alloy reveals the role of solutes Ni and Sn (segregation, distribution and concentration) on the high-temperature oxidation behavior. The resulting experiment and calculation presented that the reduction of intra/inter-granular segregation and adjustment of concentration of solutes Ni and Sn via heat treatment could prevent the diffusion of oxygen in surface and interface layers, form the compact and uniform oxide layers and finally improve the oxidation resistance of Cu alloys.