空气中１０００℃、１０５０℃、１１００℃恒温氧化及１０００℃循环氧化的热重分析（ＴＧＡ）表明，Ｍ１７Ｆ合金的氧化速率比Ｍ１７合金的慢，氧化皮对基体的粘附性也强于Ｍ１７合金的。金相、扫描电镜、能谱（ＥＤＡＸ）、Ｘ衍射和电子探针的观察分析发现在Ｍ１７合金，γ／γ’基体上ＭＣ（Ｍ＝Ｔｉ，Ｖ等）碳化物呈细条状析出，且大多分布在析出的大块状的γ相和（γ＋γ’）共晶的周围；γ’相的不均匀析出提高了合金表面局部区域的Ｔｉ／Ｃｒ比，不利于氧化皮的均匀生长，而细长条状的碳化物增大了合金的氧化深度并引起内氧化；而Ｍ１７Ｆ合金在氧化皮／合金基体界面形成了一连续的Ｔａ（Ｔｉ）的氧化物带，收善了氧化性能。Ｍ１７合金表面注入１×１０（１７）Ｙ＋／ｃｍ２后，改变了氧化层的生长机制，促进了保护性的Ｃｒ２Ｏ３氧化层的快速形成
Both isothermal (at 1000℃,1050℃, 1100℃) and thermal cyclic(at 1000℃) oxidation performance of superalloys M17F and M17 in air were studied through TGA, XRD, SEM/EDAX and SEM/EPMA.The oxidation rate of M17F was much lower than that of M17, and the scale on M17F was more adhesive than that on M17. Such differences might result from the difference in the microstructure and refractory elements of the two superalloys. The irregular precipitation of γ' and/or (γ+γ')eutectic plates with higher Ti/Cr ratio resulted in rapid oxidation at the corresponding areas and thereby in the uneven scale on M17, while γ' precipitates were fine and dispersed in M17F. Furthermore, the rapid oxidation of the long strip-like MC carbides in M17 prevented the alloy from developing a protective scale. Elemental Ta in M17F brought about a Ta-rich oxide ribbon keying at the oxide scale/alloy substrate interface and thereby improved the cyclic oxidation performance of the alloy. Implanted Y+ favored the formation of a protective Cr2O3 layer in the scale and was thereby beneficial to the improvement of the oxidation-resistance of the alloy.
参考文献
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| [4] | 彭晓,李铁藩,李美栓等．中国稀土学报,1994,12:3282LitzJ,RahmelA |
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