EFFECTS OF Dy ON THE MICROSTRUCTURE AND SPALLATION FAILURE OF THE ALUMINA SCALES GROWN ON NiAl
EFFECTS OF Dy ON THE MICROSTRUCTURE AND SPALLATION FAILURE OF THE ALUMINA SCALES GROWN ON NiAl
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DOI：
10.1142/s0217979210066239
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发表时间：
2010-06
影响因子：
1.7
通讯作者：
Hongbo Guo;Xiaoyang Wang;S. Gong
中科院分区：
文献类型：
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作者：
Hongbo Guo;Xiaoyang Wang;S. Gong
NiAl作为高温抗氧化保护涂层材料的潜力越来越受到人们的关注。采用电弧熔炼法制备了掺镝（Dy）的NiAl合金。合金的循环氧化在1200°C下进行。研究了Dy作为反应元素对NiAl表面氧化铝膜微观结构和失效的影响。对于熔融态合金，Dy主要沿沿着晶界析出，部分以DyNi 2 Al 3相形式在晶内析出。与未掺杂的NiAl合金相比，Dy掺杂的NiAl合金氧化膜的微观结构发生了很大的变化，脊状的Al2O3氧化膜变得不那么明显。等轴氧化铝膜在NiAl上生长，而柱状氧化铝在Dy掺杂的NiAl上生长。Dy掺杂剂防止氧化皮起皱和在氧化皮下形成空腔。由于这一点，氧化皮粘附性显著改善。对于Dy掺杂的NiAl，氧化膜失效主要发生在富含Dy的氧化物突起周围。
NiAl has attracted increasing attentions because of its promising potential as protective coating materials for high temperature oxidation resistance. In this paper, Dysprosium (Dy) doped NiAl alloys were produced by arc melting. Cyclic oxidation of the alloys was carried out at 1200°C. The effects of Dy as a reactive element on the microstructure and failure of alumina scales on NiAl were investigated. For the melted alloy, Dy was mainly precipitated along the grain boundary and some within the grains in the form of DyNi2Al3 phase. Compared to Al2O3 scale formed on the undoped NiAl alloy, the microstructure of the scale was greatly changed and the ridge-like Al2O3 scale became less distinct on Dy-doped NiAl. The equi-axed alumina scale grew on NiAl, whereas the columnar alumina developed on Dy doped NiAl. The Dy dopant prevented the oxide scale from rumpling and the formation of cavities beneath the oxide scale. Due to this, the oxide scale adhesion was significantly improved. For Dy-doped NiAl, the scale failure mostly occurred surrounding the oxide protrusions where were rich in Dy.