Interface engineering in mullite fiber/mullite matrix composites
Interface engineering in mullite fiber/mullite matrix composites
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DOI：
10.1016/j.jeurceramsoc.2007.03.008
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发表时间：
2008
影响因子：
5.7
通讯作者：
K. Chawla
中科院分区：
文献类型：
--
作者：
K. Chawla
莫来石纤维/莫来石基复合材料因其固有的高温抗氧化性而备受关注。莫来石比氧化铝具有更好的抗蠕变性。然而，氧化物之间的化学相互作用通常非常严重;结果是在韧性方面没有超过单片莫来石的增益。即使在没有化学键合的情况下，也可以存在强机械键合组分。这源于由于热膨胀失配和/或界面的表面粗糙度引起的径向压应力。因此，界面区的微观结构和行为是获得有效控制复合材料损伤和提高韧性的关键因素。这一机构的莫来石/莫来石复合材料的工作表明，生产完全致密，坚韧氧化物/氧化物复合材料的界面工程的可行性。涂层如BN单独或SiC/BN双涂层对莫来石纤维/莫来石基复合材料有效地起作用，因为它们在室温下提供非脆性断裂和增加的断裂功。看起来，为了在空气中的高温下使用，需要在氧化物中识别BN的结构类似物。
Mullite fiber/mullite matrix composites are attractive because of their inherent oxidation resistance at high temperatures. Mullite has better creep resistance than alumina. However, chemical interactions between oxides are often very severe; with the result no gain is made over monolithic mullite in terms of toughness. Even in the absence of chemical bonding, a strong mechanical bond component may be present. This originates from radial compressive stress due to thermal expansion mismatch and/or the surface roughness of interface. Thus, the microstructure and behavior of the interface region are the key factors in obtaining an effective control of damage in composites and enhancement of toughness. This body of work on mullite/mullite composites shows the feasibility of producing fully dense, tough oxide/oxide composites by interface engineering. Coatings such as BN alone or SiC/BN double coating function effectively for mullite fiber/mullite matrix composites in that they provide a nonbrittle fracture and increased work of fracture at room temperature. It would appear that for use at high temperatures in air, one needs to identify structural analogs of BN among oxides.