GOALI: Use Of Microsample Testing To Characterize and Model Bond Coat Performance and TBC Life

高温热障涂层（TBC）的一个关键组成部分是粘结层，因为它既提供了热生长的氧化层，对TBC的附着至关重要，特别是那些通过物理气相沉积沉积的涂层，也提供了涂层所处的机械基础。此次GOALI拨款的合作，加入了约翰霍普金斯大学与航空航天工程师和科学家的专业知识以及通用电气飞机发动机公司的测试能力共同开发的新型微样品拉伸、蠕变和疲劳测试能力。这项合作研究的总体目标是表征粘结层的变形行为，并将其机械性能和失效过程与TBC寿命联系起来。所采用的微样品测试方法允许以传统方法无法实现的方式表征小规模和高度尺度特异性涂层和性能。微样品的使用提供了一个独特的机会来测量热膨胀的高温系数，杨氏模量，拉伸，蠕变和疲劳强度的沉积和热循环的粘结层。对破坏机制和底层微观结构的详细观察将用于评估应变调节、微裂纹、空洞形成、元素扩散、晶界滑动和其他被认为影响TBC性能的破坏过程的重要性。除了生成急需的设计数据外，该合作还为使用有限元建模计算进行寿命预测评估提供了机制基础。GOALI的工作包括紧密结合的研究活动和年度人员交流，使学生和教师与GE-AE的工程师和科学家直接接触。这样做通过提供宝贵的技术和工业经验，拓宽了JHU学生的教育。GE-AE的好处包括拥有独特的实验设施，能够专注于基础研究，而不是在工业环境中进行。该基金由MPS多学科活动办公室和材料研究部的金属研究计划共同资助。航空发动机涡轮的性能和耐用性与放置在热截面部件上的TBC的性能和耐用性越来越密切相关。TBC现在被广泛用于提高涡轮部件的耐久性，但使用TBC来提高进口温度，从而提高性能，目前被可能的碎裂所抑制。如果TBC是用来提高发动机性能，这是至关重要的，这些涂层被可靠地保留在金属基板上，他们的目的是保护

9986752Hemker A key component of high temperature thermal barrier coatings (TBC's) is the bond coat since it provides both the thermally grown oxide layer critical to the attachment of TBC's, especially those deposited by physical vapor deposition, and the mechanical foundation upon which the coating sits. The collaboration in this GOALI grant joins the novel microsample tensile, creep and fatigue testing capabilities developed at Johns Hopkins with the expertise of aerospace engineers and scientists and the test capabilities at General Electric Aircraft Engines. The overall goal of this collaborative study is to characterize the deformation behavior of bond coat layers and relate their mechanical performance and failure processes to TBC life. The microsample testing approach adopted permits characterization of small-scale and highly scale-specific coatings and properties in a way not possible by conventional means. The use of microsamples provides a unique opportunity to measure the high temperature coefficient of thermal expansion, Young's modulus, and tensile, creep and fatigue strength of both as-deposited and thermally cycled bond coat layers. Detailed observations of the failure mechanisms and underlying microstructure will be used to assess the importance of strain accommodation, micro-cracking, void formation, elemental diffusion, grain boundary sliding, and other failure processes thought to affect TBC performance. The collaboration provides a mechanistic foundation for life prediction assessment using finite element modeling calculations in addition to generating much needed design data. The GOALI effort includes closely meshed research activities and yearly personnel exchanges, placing students and faculty in direct contact with engineers and scientists at GE-AE. Doing so broadens the education of the JHU students by providing invaluable technological and industrial experience. The benefits to GE-AE include the availability of unique experimental facilities and the ability to focus on fundamental research not otherwise undertaken in an industrial environment. The grant is jointly funded by the MPS Office of Multidisciplinary Activities and the Metals Research Program in the Division of Materials Research.%%%The performance and durability of aircraft engine turbines has become more closely linked to the capability and durability of TBC's that are placed on hot section components. TBC's are now widely used to increase durability of turbine components, but the use of TBC's to increase inlet temperatures, and thus performance, is currently inhibited by the possibility of spallation. If TBC's are to be used to increase engine performance, it is essential that these coatings be retained reliably on the metallic substrates they are designed to protect.***