(1. 江蘇科技大學(xué)(張家港) 冶金與材料工程學(xué)院，蘇州 215600；
2. 江蘇省(沙鋼)鋼鐵研究院 板帶研究室，蘇州 215625；
3. 鋼鐵研究總院 工程用鋼研究所，北京 100081)
摘 要: 采用準(zhǔn)靜態(tài)拉伸實(shí)驗(yàn)研究鋼/鋁復(fù)合板在1×10-4~1×10-2 s-1應(yīng)變速率范圍的拉伸力學(xué)性能與變形行為，通過掃描電鏡表征分析復(fù)合界面的組織演變與失效機(jī)理。結(jié)果表明：鋼/鋁軋制復(fù)合界面生成厚度約8 μm、含有少量金屬間化合物Fe2Al5和Fe4Al13的過渡層。復(fù)合板的強(qiáng)度與鋼、鋁層之間滿足混合法則，界面具有強(qiáng)化作用但易產(chǎn)生微裂紋，界面斷裂失效和基層應(yīng)變硬化導(dǎo)致應(yīng)力-應(yīng)變曲線波動(dòng)。高應(yīng)變速率加載使界面層急劇斷裂，曲線波動(dòng)程度增大，但斷口的界面分離程度減小。準(zhǔn)靜態(tài)拉伸過程，鋼/鋁界面最先萌生裂紋，層間附加應(yīng)力引起界面裂紋長大并擴(kuò)展至鋁層內(nèi)部，鋼層隨后頸縮導(dǎo)致復(fù)合板斷裂失效。提高鋼/鋁界面的結(jié)合強(qiáng)度可以改善層狀復(fù)合板的變形協(xié)調(diào)性和力學(xué)性能。
關(guān)鍵字: 鋼/鋁復(fù)合板；拉伸試驗(yàn)；復(fù)合界面；斷裂；力學(xué)性能
（1. School of Metallurgy and Materials Engineering, Jiangsu University of Science and Technology (Zhangjiagang), Suzhou 215600, China;
2. Department of Plate and Strip, Jiangsu (Shagang) Institute of Research of Iron and Steel, Suzhou 215625, China;
3. Department of Structural Steels, Central Iron and Steel Research Institute, Beijing 100081, China）
Abstract:The tensile tests of steel/aluminum composite sheet were conducted at strain rate ranging from 1×10-4 s-1 to 1×10-2 s-1. It was aimed to study the deformation behavior and failure mechanism. The results show that a transition layer with thickness of about 8 μm and a few of intermetallic compounds Fe2Al5 and Fe4Al13 phases forms at the steel/aluminum roll-bonded interface. The strength of the composite sheet satisfies the mixing rule with the individual layers. The interface plays an important role in the strengthening of composite sheet. However, the bonding interface is prone to fracture due to microstructural defects. The failure of the interface and the strain hardening of the individual layer cause the stress-strain curve to fluctuate. High strain rate loading leads to the sharp break of interface layer and the obvious fluctuation of tensile curve. During the quasi-static tensile process, the cracks firstly initiate in the steel/aluminum interface, and the additional stress between the layers causes the cracks to grow and expands into aluminum layer. The steel layer subsequently necks and causes the composite sheet to fracture. By increasing the bonding strength of steel/aluminum interface, the deformation coordination and mechanical properties of the composite sheets can be improved.
Key words: steel/aluminum composite sheet; tensile test; bonding interface; fracture; mechanical properties
