Clarification of Thermal-Mechanical Failure Mechanism and Proposition of Control Plan for Failure in Thermal Barrier Coating System

热障涂层系统热机械失效机理的阐明及失效控制方案的提出

• 批准号: 18560678
• 负责人: TAKAHASHI Satoru
• 金额: $ 2.4万
• 依托单位: Tokyo Metropolitan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560678/
• 关键词: High Temperature Materials; Thermal Barrier Coating; Failure Analysis; In-situ Observation; 遮熱コーディング; 溶射

Thermal barrier coating (TBC) systems have become today one of the indispensable technologies for hot-section components of advanced gas turbines. It is required to clarify the failure mechanism of TBC system under the complex modes of thermal-mechanical loadings for designing reasonably the advanced TBC system with more superior durability and reliability.In the present study, in situ observation apparatus of TBC system failure behavior under various mechanical loadings was developed. Then, the crack initiation and propagation behavior of TBC systems with different coating microstructure were investigated under various mechanical loadings such as static creep dynamic fatigue and so on at room and elevated temperature and proposed the control plan for thermal-mechanical failure. The summary of results obtained is as follows ;1)Under static creep loading, TBC system exhibits the typical creep rupture behavior with the manner of the nucleation and coalescence of mainly the grain boundary cracks in the alloy substrate interior,because the propagation of macrocracks developed in the ceramic top-coat (TC) into the metallic bond-coat (BC) and substrate can be prevented effectively by virtue of the stress relief due to the large magnitude of plastic flow in the BC layer at the elevated temperature which is higher than the ductile-brittle transition temperature (DBTT) of the BC.2)Under dynamic fatigue loading, the failure behaviour of TBC systems depends strongly on the TC microstructure and the geometric morphology of the TC/BC interface. For all TBC systems, the concave region on the TC/BC interface and tip of macrocrack penetrating through the TC provides a nucleation site for the fatigue crack regardless of the DBTT of BC.

热障涂层（TBC）系统如今已成为先进燃气轮机热段部件不可或缺的技术之一。为了合理设计具有更高上级耐久性和可靠性的TBC系统，需要弄清TBC系统在复杂热-机械载荷模式下的失效机理。然后，研究了不同涂层组织的热障涂层系统在室温和高温静态蠕变、动态疲劳等多种机械载荷作用下的裂纹萌生和扩展行为，提出了热机械失效的控制方案。所得结果汇总如下; 1）在静态蠕变载荷下，TBC体系表现出典型的蠕变断裂行为，主要是晶界裂纹在合金基体内部形核和合并，由于宏观裂纹在陶瓷面层（TC）中扩展到金属粘结层（BC），在高于BC的韧脆转变温度（DBTT）的高温下，BC层中大量的塑性流动可有效地消除应力，从而有效地防止基体的断裂。2）在动态疲劳载荷下，TBC体系的破坏行为强烈地依赖于TC微观结构和TC/BC界面的几何形态。对于所有TBC系统，TC/BC界面上的凹陷区域和穿透TC的宏观裂纹尖端为疲劳裂纹提供了形核位置，而与BC的DBTT无关。

项目成果

EB-PVD法によるTBCシステムの静的負荷条件における損傷挙動のその場観察

EB-PVD法原位观察静载条件下TBC系统损伤行为

• 发表时间: 2007
• 作者: M.Kumar;T.Okazaki;Y.Ando;K.Hatanaka;高橋 智
• 通讯作者: 高橋 智

In-situ Observation of Mechanical Failure Behavior in Electron Beam Physical Vapor Deposited Thermal Barrier Coating System under Static Loading.

静态载荷下电子束物理气相沉积热障涂层系统机械失效行为的原位观察。

• 发表时间: 2007
• 作者: Satoru;Takahashi
• 通讯作者: Takahashi