In order to explore effect of silicon on the oxidation resistance of Ni-based superalloys, the cyclic oxidation behavior of Ni–15Cr–5Al–xSi (x = 0, 1, 3, 5 wt%) at 1100 °C was studied. The results show that the addition of Si promotes the nucleation of metastable and stable alumina, which facilitates selective Al oxidation to enable a rapid formation of continuous metastable and stable alumina scales, which in turn greatly enhances the oxidation resistance of alloys. The addition of alloyed Si can also enhance the adhesion between matrix and oxide scale. It was determined that the optimal Si content for scale adherence was 3 wt%. However, the adhesion between oxide scale and matrix decreased with higher Si content. One reason could be that the volume shrinkage caused by transformation from metastable alumina to stable alumina. The other is an increase in the thermal stresses generated in the scale with higher silicon contents.

中文翻译：

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Ni-15Cr-5Al-xSi (x = 0, 1, 3, 5 wt%) 合金在 1100 °C 空气中的氧化行为

为了探索硅对镍基高温合金抗氧化性的影响，研究了 Ni-15Cr-5Al-xSi (x = 0, 1, 3, 5 wt%) 在 1100 °C 下的循环氧化行为。结果表明，Si的加入促进了亚稳态氧化铝的成核，促进了Al的选择性氧化，使连续亚稳态氧化铝鳞片快速形成，从而大大提高了合金的抗氧化性。添加合金硅还可以增强基体与氧化皮之间的附着力。经确定，用于结垢附着的最佳 Si 含量为 3 wt%。然而，随着Si含量的增加，氧化皮和基体之间的附着力下降。原因之一可能是由亚稳态氧化铝转变为稳定氧化铝引起的体积收缩。