Integrated Experiment and Atomistic Computation on Moisture-Induced Interfacial Embrittlement

湿致界面脆化的综合实验和原子计算PI： 斯科特·X金属陶瓷复合材料、电子封装以及用于热防护、耐磨和抗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，湿致界面脆化是这些界面材料在含湿环境中应用的主要机械失效之一，并成为一个严重的技术问题。缺乏对（i）水分如何与金属/陶瓷界面结合反应并降低界面强度以及（ii）哪种类型的界面对湿致脆化敏感是新界面材料（如涂层和多层）设计和应用的障碍的理解。本项目将通过实验和原子模型预测相结合，结合原位X射线光电子能谱（XPS）测试和第一性原理计算，重点研究界面处水分诱导韧脆转变的机制。提出的AFM针尖/水分/衬底相互作用的实验将打开一个新的方法来量化与水分效应的原子间相互作用。此外，该项目将整合研究和教育（一）提供培训的研究生和本科生，（二）课程开发？界面材料和特性，(iii)通过目前的少数民族工程指导计划，增加代表性不足的群体参与研究，以及（iv）通过互联网探索者和匹兹堡卡内基科学博物馆，向小学推广，让年轻学生接触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.