铜包铝复合材料界面金属间化合物及形成机理

摘要

采用垂直充芯连铸工艺制备了直径为12 mm、铜层厚度为2 mm的铜包铝复合材料.通过SEM、XRD和TEM对界面金属间化合物的种类和形态进行了研究.研究结果表明,Cu/Al界面主要由层状γ1(Cu9Al4)相、胞状θ(CuAl2)相和α(Al)+θ(CuAl2)共晶组成,特别是在界面组织中观察到残留的针状Cu3Al2+x相.通过比较γ1(Cu9Al4)和ε2(Cu3Al2+x)的形核驱动力,证明了ε2(Cu3Al2+x)相优先在界面处形成.此外,完整揭示了铜包铝复合材料界面形成机理.%Copper cladding aluminum (CCA) rods with the section dimensions of 12 mm in diameter and 2 mm in sheath thickness were fabricated by vertical core-filling continuous casting (VCFC) technology. The kinds and morphology of interfacial intermetallic compounds (IMCs) were investigated by SEM, XRD and TEM. The results showed that the interfacial structure of Cu/Al was mainly composed of layeredγ1(Cu9Al4), cellularθ(CuAl2), and α(Al)+θ(CuAl2) phases. Moreover, residual acicularε2(Cu3Al2+x) phase was observed at the Cu/Al interface. By comparing the driving force of formation forε2(Cu3Al2+x) andγ1(Cu9Al4) phases, the conclusion was drawn that the ε2(Cu3Al2+x) formed firstly at the Cu/Al interface. In addition, the interfacial formation mechanism of copper cladding aluminum composites was revealed completely.