新型钴基高温合金成分设计的研究进展

Research Progress on Composition Design of Novel Cobalt Based Superalloy

传统钴基高温合金的强化机制为固溶强化和碳化物强化,弱于有序γ′相沉淀强化的镍基高温合金的强化效果,日本学者发现了有序γ′相强化的Co-Al-W系新型钴基高温合金,其强化效果明显优于传统钴基高温合金。由于新型钴基高温合金具有较传统镍基高温合金更高的承温能力以及更加优异的高温抗蠕变性能和抗氧化性能,因此被认为是最具潜力的航空发动机热端材料之一,近年来得到迅速发展。基于国内外学者对新型钴基高温合金的研究成果,系统总结多种合金元素(如Ta,Ti,W和Nb等)对新型钴基高温合金组织和性能的影响。在组织方面,总结合金元素对合金相变温度、γ′相的体积分数及形态、γ′相的尺寸、γ/γ′两相晶格错配度和有害相的影响;在性能方面,总结合金元素对合金抗氧化性能、力学性能及抗蠕变性能的影响,以期为新型钴基高温合金的成分设计提供参考。最后对新型钴基高温合金成分的高效率设计进行展望。

The strengthening mechanism of traditional cobalt-based superalloys is solid solution strengthening and carbide strengthening whereas,both solid solution strengthening and carbide strengthening are weaker than that of nickel-based superalloys with orderedγ′precipitation.Japanese scholars discovered a novel type of Co-Al-W superalloys with orderedγ′phase strengthening,and its strengthening effect is significantly better than that of traditional cobalt-based superalloys.Compared with traditional nickel-based superalloys,the novel cobalt-based superalloys have higher temperature capability,more excellent high temperature 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 research 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 ofγ′phase,the size ofγ′phase,the lattice misfit ofγ/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.