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TGO界面特征对热障涂层残余应力的影响

Effect of TGO topography on TBCs residual stresses

  • 摘要: 采用非线性有限元方法模拟计算了热障涂层中陶瓷层(TCC)及粘结层(BC)与热生长氧化物(TGO)层界面的残余应力的分布,计算过程中,考虑到了材料物性的非线性特征及界面形貌特征的影响.结果表明,形貌单元尺寸及分布密度对TGO界面应力有明显的影响,TCC/TGO界面的应力大于BC/TGO界面的应力.在锥形坑形貌中心尖点处存在应力集中现象,且呈现最大应力值,是涂层失效的危险点,并且残余应力值随着界面形貌分布密度的增加而减小.

     

    Abstract: By using nonlinear finite element model, the residual stress distribution which was affected by interface topography of top ceramic coat(TCC), bond coat(BC) and thermally-growth oxide(TGO) interface area in thermal barrier coatings(TBCs) system was calculated.In the process of calculation, thermodynamic parameters of TCC, TGO and BC were considered.The calculating results show that the residual stress of TGO interface is affected by interface topography unit size and topography distribution density obviously.The stress on TCC/TGO interface is greater than that on BC/TGO interface.Stress concentrates at the tip of cone topography center and reaches the maximum value, which becomes the dangerous point for failure of thermal barrier coatings system.The residual stress level decreases with the increasing of topography quantity.

     

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