(西安交通大學(xué) 金屬材料強(qiáng)度國(guó)家重點(diǎn)實(shí)驗(yàn)室，西安 710049)
摘 要: 通過(guò)單軸拉伸試驗(yàn)研究恒定調(diào)制周期的聚酰亞胺基體Cu/Nb納米金屬多層膜的延性對(duì)調(diào)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(shù)深入分析多層膜的異質(zhì)約束效應(yīng)對(duì)斷裂行為的影響。結(jié)果表明：隨著調(diào)制比的增加，多層膜的延性單調(diào)減小，出現(xiàn)由剪切型向張開(kāi)型斷裂模式的轉(zhuǎn)變。當(dāng)調(diào)制比小于某一臨界值時(shí)，調(diào)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(duì)脆相Nb層中萌生的微裂紋擴(kuò)展的約束作用。
關(guān)鍵字: 納米金屬多層膜；延性；斷裂行為；調(diào)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
