柔性基底上纳米金属多层膜的断裂与屈曲行为强烈地依赖于调制结构、组元材料以及膜基界面结合等因素，这些因素对多层膜断裂与屈曲行为的单一和耦合影响目前尚不清楚，限制了人为调控的可能。基于前期初步研究结果及所提炼的科学问题，本申请将以柔性聚酰亚胺基底上的fcc/bcc类型(Cu/Cr)和fcc/hcp类型(Cu/Zr)两类纳米金属多层膜作为研究对象，分别设计调制周期、组元匹配和膜基界面结合对比实验，通过定量表征多层膜单轴拉伸断裂应变和屈曲应变，分析相关断裂模式和屈曲模式，尝试揭示尺寸效应、组元效应和膜基界面结合对多层膜断裂与屈曲行为的单一和耦合影响，阐明多层膜断裂与屈曲行为的主要影响因素。在此基础上建立相关断裂和屈曲理论模型，提出屈曲模式转变的判据，构建起微观组织/结构-力学性能-断裂与屈曲行为之间的内在关联，为柔性电子领域界面结构设计和性能优化提供理论基础和技术指导。

The cracking and buckling behaviors of nanostructured metallic multilayer films adherent to compliant substrates strongly depend on the modulation structures, the constituent phases, and the film/substrate interfacial adhesion. However, the separate and coupling effects of their influencing factors on the cracking/buckling behaviors are still poorly understood, which limits the possibility of artificial tuning. Based on the applicant’s preliminary experimental results and the scientific point derived, here in this project two sets of polyimide-supported nanostructured metallic multilayer films, i.e., fcc/bcc Cu/Cr and fcc/hcp Cu/Zr, will be comprehensively studied to clarify the unknown issues. The cracking and buckling behaviors of the multilayer films with different modulation periods, constituents and interfacial adhesion will be systematically investigated in comparison by quantitative characterization of the cracking strain, buckling strain, fracture mode and buckling mode during uniaxial tension. This project is aimed to (i) reveal the individual and coupling effects of modulation period, constituent and interfacial adhesion, respectively; (ii) clarify the key factor predominantly controlling the cracking behaviors and buckling behaviors, respectively; (iii) develop the cracking and buckling models and propose a criterion to rationalize the transition in buckling modes. Based on these studies, the relationship of microstructures - mechanical properties - cracking and buckling behaviors of the nanostructured metallic multilayer films could be well understood. The results will be helpful for providing theoretical basis and technical guidance for structure design and property optimization in the field of flexible electronics.