热障涂层高温TGO生长变化

TGO growth of high temperature thermal barrier coatings

通过Abaqus有限元分析软件对热障涂层在高温氧化过程中的热氧化物层(themally growth oxide,TGO)生长机制进行研究.结果表明,当高温氧化到100 h时,TGO厚度由初始的0.5μm生长至6.7μm且在不同位置TGO的厚度略微不同.随着高温时间的增加,热障涂层在TGO的波峰、波谷以及涂层边界处容易出现应力较大值,且和周围材料相比应力明显较大,此时,这些位置容易达到材料开裂临界应力,形成裂纹萌生点,使得涂层失效.在高温氧化过程中,涂层吸收总能量为43.6 J,其中少部分转化为涂层变形所消耗的能量,剩下的能量为高温氧化过程中涂层成分改变,微观组织改变以及裂纹萌生扩展提供能量.

Growth mechanism of thermally growth oxide( TGO) in thermal barrier coatings( TBCs) was investigated by finite element analysis software ABAQUS. After high temperature oxidation for 100 hours,the thickness of TGO increased from 0. 5μm to 6. 7 μm. With the increasing of high temperature oxidation,stresses in the peaks,valleys and interface of TGO were obviously larger than in other places. Meanwhile,cracks were prone to initiate and propagate at these locations,and eventually led to spalling of the entire coating. During high temperature oxidization,the total absorbed energy of coating was 43. 6 J,some of which was consumed for coating deformation,and the remaining for changes of coating composition and microstructure,and crack propagation.