| 摘 要： | Isothermal oxidation resistance,oxide scale evolution and failure mechanism of Ce-doped Co-Al-W-MoTa-B alloy(0.01 at%,0.05 at%,0.10 at% and 0.20 at% Ce)exposed at 800℃ were compared.The 0.01 Ce and 0.05 Ce alloys were consisted of γ/γ' coherent micro structure,while the κ-Co_3 W compound precipitated at the grain boundary of the 0.1 OCe and 0.20 Ce alloys in addition to the γ/γ'microstructure.The oxidation kinetics curves of the Cedoped alloys exhibited a parabolic time dependence on the weight gain.With an increasing nominal Ce content,the weight gain of the Co-Al-W-Mo-Ta-B alloys monotonically decreased.An oxide scale composed of a dense and uniform outer Co_3 O_4+CoO layer,a middle CoAl_2 O_4 and CoWO_4 compound layer and an inner Al_2 O_3 layer.The excellent oxidation resistance of 0.2 Ce alloy was mainly attributed to a shorter incubation stage for the formation of the continuous and protective Al_2 O_3 layer and the thickest Al_2 O_3 layer during entire oxidation process.
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