Research Progress on Composition Design of Novel Cobalt Based Superalloy
The strengthening mechanism of traditional cobalt-based superalloys is solid solution strengthening and carbide strengthening whereas,both solid solution strength-ening and carbide strengthening are weaker than that of nickel-based superalloys with ordered γ′ precipitation.Jap-anese scholars discovered a novel type of Co-Al-W superal-loys with ordered γ′ phase strengthening,and its strengthe-ning effect is significantly better than that of traditional co-balt-based superalloys.Compared with traditional nickel-based superalloys,the novel cobalt-based superalloys have higher temperature capability,more excellent high tempera-ture creep resistance and oxidation resistance,therefore,the novel cobalt-based superalloys are considered to be the most potential aeroengines hot side materials and have developed rapidly in recent years.In this review,based on the re-search results of the novel cobalt-based superalloys by scholars at home and abroad,the effects of various alloying elements(such as Ta,Ti,W,Nb and so on)on the structure and properties of novel cobalt-based superalloys were systematically summarized.In terms of microstructure,the effects of alloying elements on transformation temperature,volume fraction and morphology of γ′ phase,the size of γ′ phase,the lattice misfit of γ/γ′ two phase and the harmful phase were summarized.Meanwhile,in terms of properties,the effects of alloying elements on oxidation resistance,mechanical property and creep resistance of the alloy were also discussed,it is expected to provide reference for the composition design of novel cobalt-based superalloys.Finally,the high efficiency design of novel cobalt-based superalloys are prospected.
Co-based superalloycomposition designγ′ phasemicrostructure and propertiescreep
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