The early stages of development of α-Al2O3 scales on Fe-Cr-Al and Fe-Cr-Al-Y Alloys at high temperature
The early stages of development of α-Al2O3 scales on Fe-Cr-Al and Fe-Cr-Al-Y Alloys at high temperature
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Fe-Cr-Al和Fe-Cr-Al-Y合金高温下α-Al2O3氧化皮发展的早期阶段
DOI：
10.1007/bf00604565
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
F. Stott
中科院分区：
文献类型：
--
作者：
F. A. Golightly;G. Wood;F. Stott
本文研究了Fe-14%Cr-4%Al、Fe-27%Cr-4%Al和含0.008%Y、0.023%Y和0.8%Y的类似合金在1000和1200 ℃下在1atm氧气中氧化初期氧化物的发展。在所有的情况下，一个稳定状态的α-Al 2 O3层迅速建立后，一些初步形成的瞬态氧化物富含铁和铬。对于不含钇的合金，对于含铬较高的合金和在较高的温度下更快地实现稳态情况。由于α-Al_2O_3层在合金粗糙基体处的发展速度比在平坦的合金-氧化物界面处的发展速度慢，因此，形成的瞬态氧化物的量也由试样的表面形貌决定。随着完整α-Al 2 O3层的形成，由于氧化物中的高压缩生长应力，氧化物在一定温度下形成了卷曲的氧化物形态。这些产生以下的反应之间的氧离子扩散向内向下的氧化物晶界和铝离子扩散向外通过大块氧化物。这导致氧化物的横向生长和合金在平行于合金-氧化物界面的方向上的塑性变形和移动。钇的加入促进了铝的选择性氧化。此外，钇被结合到生长的氧化物中，在那里它改变了生长机制，减少了高压缩生长应力的产生，从而减少了回旋氧化物形态的发展。
The development ofthe oxides on Fe-14%Cr-4%Al, Fe-27%Cr-4%Al, and similar alloys containing 0.008% Y, 0.023% Y, and 0.8% Y has been investigated during the early stages of oxidation in 1 atm oxygen at 1000 and 1200°C. In all cases, a steady-state α-Al2O3layer is established rapidly, after some initial formation of transient oxides rich in iron and chromium. For the yttrium-free alloys the steady-state situation is achieved more rapidly for the higher chromium-containing alloy and at the higher temperature. The amount of transient oxide formed is also determined by the specimen surface topography since the development of the α-Al2O3layer is less rapid at the base of alloy asperities than at a flat alloy-oxide interface. Following establishment of the complete α-Al2O3layer, the oxide develops a convoluted oxide morphology at temperature, due to high compressive growth stresses in the oxide. These arise following reaction between oxygen ions diffusing inward down the oxide grain boundaries and aluminum ions diffusing outward through the bulk oxide. This results in lateral growth of the oxide and plastic deformation and movement of the alloy in a direction parallel to the alloy-oxide interface. The addition of yttrium to the alloys promotes the selective oxidation of aluminum. Also, the yttrium is incorporated into the growing oxide where it changes the mechanism of growth, reducing the production of the high compressive growth stresses and thus the development of the convoluted oxide morphology.