A MECHANISTIC STUDY OF OXIDATION-INDUCED DEGRADATION IN A PLASMA-SPRAYED THERMAL BARRIER COATING SYSTEM. PART I: MODEL FORMULATION
A MECHANISTIC STUDY OF OXIDATION-INDUCED DEGRADATION IN A PLASMA-SPRAYED THERMAL BARRIER COATING SYSTEM. PART I: MODEL FORMULATION
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DOI：
10.1016/s1359-6454(01)00060-x
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发表时间：
2001-05
期刊：
影响因子：
9.4
通讯作者：
E. Busso;Jianguo Lin;S. Sakurai;M. Nakayama
中科院分区：
文献类型：
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作者：
E. Busso;Jianguo Lin;S. Sakurai;M. Nakayama
研究了典型的等离子喷涂热障涂层（PS-TBC）系统的氧化降解对介观裂纹形核的陶瓷-金属界面局部应力的影响。提出了一种耦合氧化-本构模型来描述局部内外氧化过程引起的相变对金属涂层本构行为的影响。耦合的本构框架被实施到有限元方法中，并用于采用周期性单胞技术的参数研究。量化的服务，显微组织和陶瓷-金属界面参数的峰值界面应力在服务和冷却到室温的影响。参数单胞有限元分析的结果显示，导致介观裂纹成核和生长的局部应力与氧化界面的局部形态、陶瓷涂层的烧结、蠕变引起的应力松弛效应、热生长氧化物的厚度（TGO）以及施加的机械载荷有很强的依赖性。当不考虑TBC系统的机械应变时，对于约100 μ m的临界TGO厚度，陶瓷顶涂层内垂直于涂层表面的局部拉伸应力在室温下达到高达330 MPa的值。3 μm。
The effect of the oxidation induced degradation of a typical plasma-sprayed thermal barrier coating (PS-TBC) system on the local ceramic–metal interfacial stresses responsible for the nucleation of mesoscopic cracks is investigated. A coupled oxidation-constitutive approach is proposed to describe the effect of the phase transformations caused by local internal and external oxidation processes on the constitutive behaviour of the metallic coating. The coupled constitutive framework is implemented into the finite element method and used in parametric studies employing periodic unit cell techniques. The effects of service, microstructural and ceramic–metal interface parameters on the peak interfacial stresses during service and cooling to room temperature are quantified. The results of the parametric unit cell FE analyses revealed a strong dependency of the local stresses responsible for mesoscopic crack nucleation and growth on the local morphology of the oxidised interface, the sintering of the ceramic coating, stress relaxation effects due to creep, the thickness of the thermally grown oxide (TGO), and the applied mechanical loads. When no mechanical straining of the TBC system is considered, local tensile stresses normal to the coating surface within the ceramic top coating reach values of up to 330 MPa at room temperature for a critical TGO thickness of approx. 3 μm.