Integrated Experiment and Atomistic Computation on Moisture-Induced Interfacial Embrittlement

[2] Scott X. Mao，美国匹兹堡大学机械工程与材料科学系。金属-陶瓷复合材料、电子封装和用于热防护、耐磨和耐热腐蚀的环境屏障涂层都是由金属/陶瓷界面制成的。这些界面材料的可靠性在很大程度上取决于其界面性能的性质。目前，水致界面脆化是界面材料在含湿环境中应用的主要力学失效之一，成为界面材料在含湿环境中应用的重要技术问题。缺乏对以下方面的理解：(1)水分如何与金属/陶瓷界面键发生反应并降低界面强度；(2)什么类型的界面对水分引起的脆化敏感是新界面材料（如涂层和多层）设计和应用的障碍。本项目将通过实验与原子模型预测相结合，结合现场x射线光电子能谱（XPS）测试和第一性原理计算，重点研究界面湿致韧脆性转变的机理。本文提出的原子力显微镜针尖/水分/衬底相互作用实验将为原子间相互作用与水分效应的定量研究开辟一条新途径。此外，该计划将把研究与教育结合起来(i)为研究生和本科生提供培训；（ii）在？界面材料及特性？（iii）通过当前的少数民族工程指导计划增加未被充分代表的群体对研究的参与，以及（iv）通过互联网探索者和匹兹堡卡内基科学博物馆向小学和年轻学生宣传界面材料和表面工程。

Integrated experiment and atomistic computation on moisture-induced interfacial embrittlementPI: Scott X. Mao, Dept of Mechanical Engineering and Materials Science, Univ. of PittsburghMetal-ceramic composites, electronic packaging, and environmental barrier coatings used for thermal protection, abrasion, and hot corrosion resistance are all made with metal/ceramic interfaces. Reliability of these interfacial materials relies heavily on the nature of their interface performance. Currently, moisture-induced interfacial embrittlement is one of major mechanical failures and becomes a serious technological concern in the application of these interfacial materials in moisture-containing environment. Lack of the understanding on (i) how moisture react with the metal/ceramic interfacial bonds and reduce the interfacial strength and (ii) what type of interface sensitive to moisture-induced embrittlement is the barrier for new interfacial materials (such as coatings and multilayers) design and application. This project will focus on the mechanism of moisture-induced ductile to brittle transition at interface through combined experiment and atomistic model prediction with in-situ X-ray photoelectron spectroscopy (XPS) test and first-principles calculations. The proposed experiment with AFM tip/moisture/substrate interaction will open a new approach to quantify inter-atomic interaction with moisture effect. Furthermore, the project will integrate research and education by (i) providing training for graduate and undergraduate students, (ii) course development in ?interfacial materials and characteristics?, (iii) increased participation of underrepresented groups into the research through current Minority Engineering Mentoring Program, and (iv) outreach to elementary school and exposure of young students to interfacial materials and surface engineering through Internet explorers and Pittsburgh Carnegie Science Museum.