Rate Effects on the Material and Interfacial Failure of Thin Films From Static to Dynamic Loading

最近微机电系统（MEMS）的广泛应用使得对速率不敏感材料（如多晶硅）的静态和低/高周疲劳失效的研究取得了足够的进展。然而，人们对多晶硅对冲击载荷的响应知之甚少。此外，尽管金属MEMS器件在各种关键应用中变得重要，但尚未探索其显著的应变率灵敏度，导致缺乏对开发可靠器件所需的基本力学行为的理解。本项目将对多晶硅薄膜在从准静态到动态的全谱加载速率下的失效进行深入研究。此外，还将对MEMS薄膜金属材料进行实验，以揭示在每个时间尺度上发生变形和破坏的物理机制。

Abstract for CMS-0555787The recent widespread deployment of Microelectromechanical Systems (MEMS) has allowed for sufficient progress in studies focusing on the static and low/high cycle fatigue failure of rate insensitive materials such as polysilicon. However, far less is known about the response of polysilicon to impact loading. Furthermore, although metallic MEMS devices have become important in various critical applications, their significant strain rate sensitivity has not been explored, leading to a lack of understanding of the fundamental mechanical behavior required to develop reliable devices. This project will pursue an in depth investigation of the failure of polysilicon thin films over the entire spectrum loading rates from quasistatic to dynamic. Furthermore, experimentation on thin film metallic materials for MEMS will also be conducted to unravel the physical mechanisms of deformation and failure occurring at each time scale.