Metallic thin film fatigue dominated by interface character

界面特征主导的金属薄膜疲劳

• 批准号: 428963851
• 负责人: Professor Dr.-Ing. Benoit Merle
• 金额: --
• 依托单位: Erich Schmid Institute of Materials Science
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/428963851?language=en
• 关键词: Metallic; thin; film; fatigue; dominated

Thin films are used in a wide variety of applications due to the unique properties which are imparted at the micro- and nanoscale. Metal films, for example, are ideal for electrical conduction in rigid and flexible electronics and sensors, reflectors for surface mirrors on spacecraft or micro-electrical-mechanical systems (MEMS). In most applications, thin films are cyclically loaded and fail through specific fatigue mechanisms. However, sub-micrometric thin metal films behave, and thus fail, differently than bulk materials. This has been attributed to the prominent presence of an interface to a substrate and to the free surface, which strongly affects the dislocation processes pertaining to bulk fatigue. What has not yet been examined is how the type of interface controls the fatigue behavior of thin films. Interfaces can be considered as hard, created with a rigid ceramic or metal substrate, soft, next to a polymer substrate, or films can have no interface and be free-standing. It is believed that the interface type is a dominant parameter that controls the deformation mechanisms and final failure of the thin metal films as a function of the microstructure, yield strength and cyclic stress amplitude.In order to obtain deformation and failure information on thin films and their specific interface, a thorough and systematic investigation is required. It is planned to use advanced in-situ micro-mechanical testing methods to examine the role of the interface type, hard, soft or no interface, on the damage formation and failure of thin metal films. Of note is the use of sophisticated in-situ bulge testing, X-ray diffraction techniques and transmission electron microscopy with cyclic mechanical testing to observe film deformation, possible grain growth, extrusion formation, film cracking or delamination. Direct observations will enable the decoupling of the microstructural response from the interface induced mechanisms. These advanced techniques and the expertise on thin film mechanical behavior is the foundation of the proposed collaboration between the Friedrich-Alexander University Erlangen-Nürnberg (Dr. Benoit Merle) and the Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences (Dr. Megan Cordill). The unique synergies between the groups will notably allow the first systematic comparison of the fatigue behavior of similar samples in free-standing and in different supported conditions. The new knowledge about the interface specific failure mechanisms will be used to generate mechanism based models for thin film failure as well as provide improved design criteria for fatigue resistant thin film applications.

由于在微观和纳米级处赋予的独特性能，薄膜用于多种应用。例如，金属膜非常适合刚性和柔性电子和传感器的电导，这是航天器或微电力机械系统（MEMS）上表面镜的反射器。在大多数应用中，薄膜被周期性加载，并通过特定的疲劳机制失败。但是，亚微米薄金属膜的行为表现，因此失败，与散装材料不同。这归因于底物的显着存在和自由表面，这强烈影响与散装疲劳有关的位错过程。尚未研究的是界面的类型如何控制薄膜的疲劳行为。可以将界面视为难以认为是用刚性的陶瓷或金属底物创建的，柔软，在聚合物底物旁边或膜旁边，或者认为界面类型是控制薄金属膜的变形机制和最终故障的主要参数，并获得了微观结构和细胞效果的薄膜，并获得薄膜的效果，并获得了薄膜的效果，并获得了薄膜的变形。需要系统的调查。它计划使用先进的原地机械测试方法来检查界面类型，硬，软或界面对薄金属膜的损伤形成和失败的作用。值得注意的是，使用循环机械测试的复杂的原位凸起测试，X射线衍射技术和透射电子显微镜来观察膜变形，可能的晶粒生长，扩展形成，膜裂纹或分层。直接观察将使微观结构响应与界面诱导的机制的解耦。这些先进的技术和薄膜机械行为的专业知识是弗里德里希 - 亚历山大大学Erlangen-Nürnberg（Benoit Merle博士）与奥地利科学学院材料科学研究所（Megan Cordill博士）之间提议合作的基础。两组之间的独特协同作用将显然允许在独立和不同支持条件下类似样品的疲劳行为进行首次系统比较。有关界面特定故障机制的新知识将用于生成基于机制的薄膜故障模型，并为抗疲劳薄膜应用提供了改进的设计标准。