LAUSR

Abstract In this work, the oxidation behaviour of Cu-added 18 %Cr-8%Ni alloy was investigated. A duplex scale with outer Fe3O4 and inner FeCr2O4 layers was formed on the alloy surface. Due to its low oxygen affinity, Cu was ejected and segregated around the Fe3O4/FeCr2O4 interface and the scale/matrix interface during oxidation. Moreover, the supersaturation of Cu at the subsurface facilitated the extensive precipitation of Cu rich particles. As the dislocation shearing of these particles requires higher stress, the major fraction of strain energy was consumed at the subsurface. Thus, crack nucleation and propagation in the oxide scale on Cu-added alloy were suppressed.