TBC Bond Coat Properties and Dynamics

本基金资助一项实验研究，以阐明和模拟一类用于热障涂层（tbc）的新型粘结涂层材料的机械行为和热稳定性。TBC的关键组成部分之一是它的结合层，有明确的经验证据表明，在铝化物结合层中添加铂可以提高这些涂层的整体性能和可靠性。其他铂族金属（Pd, Ru, Ir， Rh和Os）被认为提供类似甚至更大的好处，但控制键合层性能的机制目前尚不清楚。拟议的研究将平行和补充一个更大的NSF-EC合作项目，研究多层多功能表面的动力学。NSF-EC研究的一个方面涉及铂族金属键合层的加工和相平衡方面，目前的研究将与NSF-EC团队密切合作，以表征ru基合金和键合层的机械行为和微观结构演变。该基金支持主要研究者和研究生参加年度研讨会，并与NSF-EC团队合作，延长学生在欧洲国家和美国之间的互访。该研究计划的总体重点将是测量单相Ru-Ni-Al-Xn和钌改性粘结层的性能，对热循环过程中发生的基材-粘结层相互作用（相互扩散、粘塑性、形态演化、裂纹形成等）有一个基本的了解，并得出一个基于科学的方案来评估潜力，并协助开发钌改性粘结层。本研究中使用的微样品拉伸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及其性能（弹性模量，屈服和蠕变强度）。这项提议的技术动机源于这样一个事实，即tbc为提高燃气涡轮发动机的温度能力和耐用性提供了巨大的机会。通过参加年度研讨会和扩大的互访，参与该项目的学生将获得宝贵的经验，了解如何在美国和欧洲进行研究。

This grant undertakes an experimental study to elucidate and model the mechanical behavior and thermal stability of a new class of bond coat materials for thermal barrier coatings (TBCs). One of the key components of a TBC is its bond coat, and there is clear empirical evidence that platinum additions to aluminide bond coats enhance the overall performance and reliability of these coatings. Other platinum group metals (Pd, Ru, Ir, Rh, and Os) are believed to provide similar or even greater benefits, but the mechanisms that govern bond coat performance are currently not well understood. The proposed study will parallel and compliment a larger NSF-EC collaborative program on the dynamics of layered multifunctional surfaces. One aspect of the NSF-EC study involves processing and phase equilibria aspects of platinum group metal bond coats, and the current study will be conducted in close collaboration with the NSF-EC team to characterize the mechanical behavior and microstructural evolution of Ru-based alloys and bond coats. The grant supports for the principal investigator and graduate students to participate in annual workshops and collaborations with the NSF-EC team with extended reciprocal visits of students between European Countries and US. The overall focus of this research program will be to measure single-phase Ru-Ni-Al-Xn and ruthenium modified bond coat properties, to develop a fundamental understanding of the substrate-bond coat interactions that occur during thermal cycling (inter-diffusion, viscoplasticity, morphological evolution, crack formation, etc.) and to derive a science-based protocol for assessing the potential and assisting in the development of ruthenium modified bond coats. The microsample tensile testing approach to be used in this study permits characterization of small-scale and highly scale-specific coatings and properties (elastic modulus, yield and creep strength) in a way not possible by conventional means. The technological motivation for this proposal is rooted in the fact that TBCs offer tremendous opportunities for increasing the temperature capabilities and durability of gas turbine engines. Through the proposed participation in annual workshops and extended reciprocal visits, the students working on this project will gain valuable experience into how research is conducted in both the U.S. and Europe.