Service Limitations for Oxidation Resistant Intermetallic Compounds
Service Limitations for Oxidation Resistant Intermetallic Compounds
复制标题
抗氧化金属间化合物的使用限制
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
D. Hull
中科院分区：
文献类型：
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作者：
J. Smialek;J. Nesbitt;W. Brindley;M. Brady;J. Doychak;R. Dickerson;D. Hull
基于 NiAl、TiAl 和 MoSi{sub 2} 的抗氧化金属间化合物在高温应用中很受关注。由于氧化，每个系统都表现出不同的寿命限制退化模式。 {β}-NiAl 形成保护性的{α}-Al{sub 2}O 鳞片。分解遵循完善的扩散控制过程，导致存活数千小时。热循环和剥落的影响已得到充分证实。 Ti{sub 3}Al 和 TiAl 化合物形成保护性较差的混合 TiO{sub 2} 和 Al{sub 2}O{sub 3} 鳞片。然而，在实际使用温度（600--800 C）下，水垢生长率低得可以接受。关键因素是由于间隙氧在几个小时内扩散而导致的脆化。基于合金开发和涂层的解决方案并不令人满意。 MoSi{sub 2}材料在非常高的温度下表现出非常低的氧化速率。然而，低温（500°C）害虫氧化可能会产生灾难性的短暂影响。材料完整性是一个关键因素。断裂的发生是由于孔隙和微裂纹中非保护性混合 MoO{sub 2}-SiO{sub 2} 鳞片的加速生长。
Oxidation resistant intermetallic compounds based on NiAl, TiAl, and MoSi{sub 2} are of interest for high temperature applications. Each system exhibits different life-limiting degradation modes due to oxidation. {beta}-NiAl forms protective {alpha}-Al{sub 2}O scales. Breakdown follows well-established diffusion controlled processes resulting in survival for thousands of hours. The effect of thermal cycling and spalling is well established. Ti{sub 3}Al and TiAl compounds form less protective mixed TiO{sub 2} and Al{sub 2}O{sub 3} scales. However at realistic use temperatures (600--800 C), scale growth rates are acceptably low. The critical factor is embrittlement due to interstitial oxygen diffusion over a matter of hours. Solutions based on alloy development and coatings have not been satisfactory. MoSi{sub 2} materials exhibit very low oxidation rates at very high temperatures. However, low temperature (500 C) pest oxidation can be a catastrophic transient effect. Material integrity is a key factor. Fracture occurs because of accelerated growth of non-protective mixed MoO{sub 2}-SiO{sub 2} scales in pores and microcracks.