(西安交通大學 金屬材料強度國家重點實驗室，西安 710049)
摘 要: 通過單軸拉伸試驗研究恒定調制周期的聚酰亞胺基體Cu/Nb納米金屬多層膜的延性對調制比的依賴性，并采用聚焦離子束/掃描電子顯微鏡(FIB/SEM)截面定量表征技術深入分析多層膜的異質約束效應對斷裂行為的影響。結果表明：隨著調制比的增加，多層膜的延性單調減小，出現(xiàn)由剪切型向張開型斷裂模式的轉變。當調制比小于某一臨界值時，調制周期越小，多層膜延性越高；反之，則多層膜延性越差。這是由于軟相Cu層對脆相Nb層中萌生的微裂紋擴展的約束作用。
關鍵字: 納米金屬多層膜；延性；斷裂行為；調制比
Cu/Nb nanostructured multilayers
（State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China）
Abstract:The dependent of ductility of polyimide-based Cu/Nb nanostructured metallic multilayers with constant modulation period on the modulation ratio was investigated by uniaxial tensile testing. The heterogeneity restriction effect of the multilayers affecting the fracture behavior was further studied through quantitative focused ion beam(FIB) and scanning electron microscope (SEM) cross-section characterization technique. The results show that the ductility of multilayers decreases with increasing modulation ratio, and the fracture mode transforms from opening to shear mode. When the modulation ratio decreases to less than a critical value, the ductility increases with decreasing modulation period. When the modulation ratio is larger than the critical value, the ductility decreases with decreasing modulation period. This can be attributed to the ductile Cu layer that can arrest the microcracks initiated in the brittle Nb layer.
Key words: nanostructured metallic multilayers; ductility; fracture behavior; modulation ratio
