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通过单轴拉伸实验并结合原位电阻测量法系统研究了恒定调制比下调制波长(λ=10—250 nm)对聚酰亚胺基体上Cu/Nb纳米金属多层膜延性和断裂韧性的影响.微观分析表明,Cu/Nb的调制结构清晰,不存在明显的互混现象.实验结果表明,随着调制波长的减小,多层膜的延性和断裂韧性均呈现非单调演变趋势,在调制波长为50 nm左右出现峰值.这是由于随着层厚的变化,脆性Nb层内起始微裂纹扩展能力和延性Cu层抑制裂纹扩展能力这两个因素之间的相互竞争关系变化引起的.采用断裂力学理论对这种竞争关系及其引起的延性和断裂韧性非单调变化趋势进行了定性分析.
The uniaxial tensile test and in situ resistance measurement were used to study the effects of modulation wavelength (λ = 10-250 nm) on the ductility and fracture toughness of Cu / Nb nano-metal multilayer films on polyimide substrate .Microanalysis shows that the modulation structure of Cu / Nb is clear and there is no obvious intermixing phenomenon.The experimental results show that the ductility and fracture toughness of multilayers show a non-monotonic evolution trend with the decrease of modulation wavelength, The modulation wavelength is about 50 nm, which is attributed to the change of mutual competition between the two factors, the initial microcrack expansion ability in the brittle Nb layer and the crack growth retardancy in the ductile Cu layer Using the theory of fracture mechanics, this competitive relationship and its non - monotonous tendency of ductility and fracture toughness were qualitatively analyzed.