The influence of bondcoat and topcoat mechanical properties on stress development in thermal barrier coating systems
The influence of bondcoat and topcoat mechanical properties on stress development in thermal barrier coating systems
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DOI：
10.1016/j.actamat.2009.01.017
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发表时间：
2009-05
期刊：
影响因子：
9.4
通讯作者：
E. Busso;Z. Qian;M. Taylor;H. Evans
中科院分区：
文献类型：
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作者：
E. Busso;Z. Qian;M. Taylor;H. Evans
采用有限元法研究了由EB-PVD YSZ表面涂层和Pt渗铝扩散粘结涂层组成的TBC系统中的应力发展。特别注意的变量，如弹性各向异性内的面漆，界面粗糙度，粘结层的蠕变强度的变化和与热生长氧化物（TGO）的形成相关的体积应变的作用。冷却过程中的粘结层氧化和热负荷会在顶涂层内产生显著的拉伸应力，并在TGO界面处产生拉伸牵引力。与屈服和塑性行为不同，粘结层蠕变是主要的应力松弛过程，强粘结层（蠕变）往往表现出较高的拉伸应力水平。决定热障涂层应力水平的另一个重要因素是顶涂层的弹性各向异性水平：弹性各向同性氧化钇稳定的氧化锆引起比横向各向同性顶涂层高得多的应力。
A finite-element study has been undertaken to investigate the stress development within a TBC system consisting of an EB-PVD YSZ topcoat and a Pt-aluminized diffusion bondcoat. Particular attention has been paid to the role of variables such as the elastic anisotropy within the topcoat, interface roughness, variation in creep strength of the bondcoat and the volumetric strains associated with the formation of the thermally grown oxide (TGO). Bond coat oxidation and thermal loading during cooling give rise to significant tensile stresses within the topcoat and tensile tractions at the TGO interfaces. Bondcoat creep, as distinct from yield and plastic behaviour, was the dominant stress relaxation process, and strong bondcoats (in creep) tended to show higher tensile stress levels. Another important factor determining thermal barrier coating stress levels was the level of elastic anisotropy of the topcoat: an elastic isotropic yttria-stabilized zirconia gave rise to considerably higher stresses than a transversely isotropic topcoat.